DS90UB941AS-Q1 Usage problems stroboscope

Honle Zhao

Part Number: DS90UB941AS-Q1
Other Parts Discussed in Thread: ALP

Tool/software:

Background: Occasional flash screen issues with LT7911+TI941 projects.

1. The software for debugging large-screen projects only changes the EDID resolution from 1920X720->800X480.

Small screen display fixed flash screen, the same firmware can be displayed normally when the LT7911D development board is connected to other DSI receiving.

Part of TI941 is abnormal

Suspected pairing problems with TI941;

(Compared with the normal display on the large screen, TI needs to explain whether the DSI->TI941->TI948 and DSI->TI941->TI926 signal paths have different requirements for DSI (DSI CLK/DSI DATA))

2. The LT7911D DSI output is configured in non-homologous mode

The repeated flash screen measurement confirms that DSI CLK in non-homologous mode is around 81MHz.

In homologous mode, DSI CLK frequency is about 83MHz,

TI needs to confirm that DSI CLK is around 81MHz.

TI941 collects why the screen flashes,

If pixclk is restored based on the DSI clock,

DSI clock bias affects recovery pixclk frequency resulting in different frame rates,

But should not cause the screen fixed flash screen;

3. TI926 output HS difference and internal recovery synchronization signal logic require TI support.

4. In addition, TI948 output LVDS also has HS/VS, whether the HS/VS logic is the same

5 months ago

0 Josh Baik 4 months ago

TI__Mastermind 22986 points

Hi Honie,

Honle Zhao said:
2. The LT7911D DSI output is configured in non-homologous mode

Could you clarify if non-homologous mode is non-burst mode or non-continuous clock mode?

What deserializer are you actually connection with when the issue is shown? DS90UB926 or DS90UB948?

Could you clarify again what the format/frequency of your DSI input to the 941AS is?

What video mode is the SoC operating in (burst mode, non-burst mode with sync pulses, or non-burst mode with sync events)?
What clock mode is the SoC DSI clock set (continuous mode or non-continuous mode)?
What is the DSI rate and what is the PCLK?

What initialization script are you using for the 941AS? Could you share the script?

While you check with the DSI source, would you be able to send a reg dump of the 941AS?

Can you provide schematics for your design?

Is this issue seen on one device out of multiple tested?

Is this something that is occurring all the time on this unit or just occasionally?

I have attached a DSI Bring-up Application Note for the 941 to help with the debug. Based on the debug flow described in the App Note, we need to take a look at the DSI source coming into the 941 with a protocol analyzer or next action item.

www.ti.com/.../snla356.pdf

Best,

Josh

0 Honle Zhao 4 months ago

Intellectual 590 points

Q：Could you clarify if non-homologous mode is non-burst mode or non-continuous clock mode?

A：Non-homologous mode means that the DSI CLK source of the LT7911D，The LT7911D's DSI clock source uses the LT7911D input pixclk in homologous mode, and the clock source uses the crystal in non-homologous mode，The LT7911D's DSI CLK is in continuous clock mode.

Q: What deserializer are you actually connection with when the issue is shown? DS90UB926 or DS90UB948?

A：DS90UB926

Q：Could you clarify again what the format/frequency of your DSI input to the 941AS is?

A：800X480, DSI 4lane，DSI CLK frequency is about 83MHz，Non-burst mode with sync pulses，Continuous-clock

Q：What initialization script are you using for the 941AS? Could you share the script?

A：The premise is that we only configured the following registers on 941, which are only used to transparently transfer I2C to the MCU on the screen for setting brightness, and the others are not set.
0x07 register is set to 0xD6
0x08 register is set to 0xD8
0x70 register is set to 0x58
0x77 register is set to 0x5A
0x03 register is set to 0x9A

Q：While you check with the DSI source, would you be able to send a reg dump of the 941AS?
A：When the problem arises in reverse, it is necessary to execute 'i2cdump -y -f 0 0x0c '

Q：Can you provide schematics for your design?

A：As attached.

Q：Is this issue seen on one device out of multiple tested?

A：This issue has occurred in multiple tests and on multiple devices.

Q：Is this something that is occurring all the time on this unit or just occasionally?

A ： Just occasionally.

0 Honle Zhao 4 months ago in reply to Honle Zhao

Intellectual 590 points

0 Honle Zhao 4 months ago in reply to Honle Zhao

Intellectual 590 points

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Honle,

Can you share the video of the flash observation?
Does this issue happen when using patgen? Or only when using DSI inputs? I would recommend the following steps with PATGEN through ALP for video control/timing source to see the issue:
- Internal - Internal timing source / Internal PCLK
- Internal timing source / External PCLK
- External - External timing source / External PCLK
- Can you follow the flow chart on page 8 to track where the issue is coming from? All you need is to match the 941AS DSI setting to SoC settings for TSKIP, CLK settings, number of Lanes, etc.
  - https://www.ti.com/lit/an/snla356/snla356.pdf?ts=1652812335521&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FDS90UB941AS-Q1
Sharing reg dump is helpful in narrowing down what factor to issue. If you don't have access to read the full reg dump, please try to read and share the contents of the following indirect registers of the 941AS:
- 0x0F
- 0x10
- 0x11
- 0x12
- 0x13
- 0x14
- 0x28
The schematic you shared is LT9711D, not 941AS.

Best,

Josh

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Honle,

The reg dump of 941AS you shared that indicates DSI_ERROR and DPHY_ERROR (0xC [6], [5]) as below. To further investigation, please provide indirect page reg dump of the 941AS or some contents of indirect registers that was already mentioned above.
Does issue ever happen when the 941AS uses patgen as steps below?
1. Internal - Internal timing source / Internal PCLK
2. Internal timing source / External PCLK
3. External - External timing source / External PCLK
Please share the init script if possible.
Do you have access to a DSI protocol analyzer? It may be helpful for us to look at the DSI source/packet structure/order coming into the 941AS.

Best,

Josh

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

1.Whether there is a malfunction or not, both 0x0c of 941 are 0x67, unchanged. It is speculated that this may be related to the loading timing of the hardware

941dump.txt

# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 78 00 00 44 40 00 00 00 00 02 ff 00    ..?.x..D@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 10 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
#
C:\Users\hiworld>adb shell
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 78 00 00 44 40 00 00 00 00 02 ff 00    ..?.x..D@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 80 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 68 08 00 00 40 00 00 00 00 02 ff 00    ..?.h?..@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
#
C:\Users\hiworld>adb shell
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 18 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 78 00 00 44 40 00 00 00 00 02 ff 00    ..?.x..D@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
#
C:\Users\hiworld>adb shell
# i2cdump -y -f 0 0x0c
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 18 00 00 9a 00 00 01 58 5a 01 11 00 67 30 00 00    ?..?..?XZ??.g0..
10: 00 00 00 cb 00 00 fe 1e 7f 7f 01 00 00 00 01 00    ...?..?????...?.
20: 00 00 25 00 00 00 00 00 01 20 20 a0 00 00 a5 5a    ..%.....?  ?..?Z
30: 00 09 00 05 0c 00 00 00 00 00 00 00 00 00 81 02    .?.??.........??
40: 10 94 00 00 00 00 00 00 00 00 00 00 00 00 00 0c    ??.............?
50: 16 00 00 00 02 00 00 02 00 00 d9 00 07 06 44 1c    ?...?..?..?.??D?
60: 22 02 00 00 10 00 00 00 00 00 00 00 00 00 20 00    "?..?......... .
70: d6 48 00 00 00 00 00 d8 4a 00 00 00 00 00 7f 00    ?H.....?J.....?.
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 82 00 78 00 00 44 40 00 00 00 00 02 ff 00    ..?.x..D@....??.
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 82 00 68 08 00 00 00 00 00 00 00 02 00 00    ..?.h?.......?..
f0: 5f 55 42 39 34 31 00 00 00 00 00 00 00 00 00 00    _UB941..........
#

3. The premise is that we only configured the following registers on 941, which are only used to transparently transfer I2C to the MCU on the screen for setting brightness, and the others are not set.
0x07 register is set to 0xD6
0x08 register is set to 0xD8
0x70 register is set to 0x58
0x77 register is set to 0x5A
0x03 register is set to 0x9A

4. no access to a DSI protocol analyzer

5. When there was a malfunction, the oscilloscope captured the timing sequence from 926 to LCD (clk, de, hs, and red [7]), and the oscilloscope displayed that all signals were shaking

The display is a red image, and the oscilloscope is in DE falling edge trigger mode
Yellow (hs) Green (clk) Red (Red [7]) Blue (DE)

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Honle,

I asked for an indirect page reg dump, not the main page. At least, please share the following indirect registers of the 941AS to investigate the issue:

0x5 & 0x0F & 0x10 & 0x11 & 0x12 & 0x13 & 0x14 & 0x28

Could you check my suggestion? It's important to break down which variable is issued.

Josh Baik said:
Does issue ever happen when the 941AS uses patgen as steps below?

Internal - Internal timing source / Internal PCLK

Internal timing source / External PCLK

External - External timing source / External PCLK

Since you said you only set GENERAL_CFG (0x3) and assigned a slave, you should check the DS90UB941AS-Q1 DSI Bring-up Guide for your setup. Register programming is highly dependent on customer use-case and configuration. It might be helpful to refer to the 4.6 section for configuring Non-Burst Mode With Sync Pulses. Based on the debug flow described in the App Note, we need to check with PATGEN, which I asked above.

Best,

Josh

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

1、iindirect page reg dump and please check if the operation process is correct

941indirectdump.txt

# ./941reg.txt
 1. get 941 version
0x55
0x42
0x39
0x34
0x31
 2. dump main page
 3. dump indirect page
64
0x00 0x00 0x00 0x1d 0x14 0x3a 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3f 
0x10 0x10 0x10 0x10 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 
0x7f 0x00 0xff 0x7f 0x00 0x00 0x00 0x00 0x05 0xff 0x3e 0xa0 0x04 0x02 0x00 0x00 
0x00 0x20 0x00 0x04 0x00 0x20 0x00 0x00 0x00 0x00 0x02 0x03 0x00 0x00 0x00 0x00
# ./941reg.txt
 1. get 941 version
0x55
0x42
0x39
0x34
0x31
 2. dump main page
 3. dump indirect page
64
0x00 0x00 0x00 0x1d 0x14 0x3a 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3f 
0x10 0x10 0x10 0x10 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 
0x7f 0x00 0xff 0x7f 0x00 0x00 0x00 0x00 0x05 0xff 0x3e 0xa0 0x04 0x02 0x00 0x00 
0x00 0x20 0x00 0x04 0x00 0x20 0x00 0x00 0x00 0x00 0x02 0x03 0x00 0x00 0x00 0x00
#
#
#
# ./941reg.txt
 1. get 941 version
0x55
0x42
0x39
0x34
0x31
 2. dump main page
 3. dump indirect page
64
0x00 0x00 0x00 0x1d 0x14 0x3a 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3f 
0x10 0x10 0x10 0x10 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 
0x7f 0x00 0xff 0x7f 0x00 0x00 0x00 0x00 0x05 0xff 0x3e 0xa0 0x04 0x02 0x00 0x00 
0x00 0x20 0x00 0x04 0x00 0x20 0x00 0x00 0x00 0x00 0x02 0x03 0x00 0x00 0x00 0x00
#
#
# ./941reg.txt
 1. get 941 version
0x55
0x42
0x39
0x34
0x31
 2. dump main page
 3. dump indirect page
64
0x00 0x00 0x00 0x1d 0x14 0x3a 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3f 
0x10 0x10 0x10 0x10 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 
0x7f 0x00 0xff 0x7f 0x00 0x00 0x00 0x00 0x05 0xff 0x3e 0xa0 0x04 0x02 0x00 0x00 
0x00 0x20 0x00 0x04 0x00 0x20 0x00 0x00 0x00 0x00 0x02 0x03 0x00 0x00 0x00 0x00
# ./941reg.txt
 1. get 941 version
0x55
0x42
0x39
0x34
0x31
 2. dump main page
 3. dump indirect page
64
0x00 0x00 0x00 0x1d 0x14 0x3a 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3f 
0x10 0x10 0x10 0x10 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 
0x7f 0x00 0xff 0x7f 0x00 0x00 0x00 0x00 0x05 0xff 0x3e 0xa0 0x04 0x02 0x00 0x00 
0x00 0x20 0x00 0x04 0x00 0x20 0x00 0x00 0x00 0x00 0x02 0x03 0x00 0x00 0x00 0x00
#

2. Can you provide operation instructions：Step by step instructions for reading and writing registers

Internal - Internal timing source / Internal PCLK
Internal timing source / External PCLK
External - External timing source / External PCLK

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Holne,

I will be back with you shortly.

Best,

Josh

0 Honle Zhao 4 months ago in reply to Honle Zhao

Intellectual 590 points

2. Can you provide operation instructions：Step by step instructions for reading and writing registers

Internal - Internal timing source / Internal PCLK

video ok

Internal timing source / External PCLK

video ok

External - External timing source / External PCLK

video abnormal

DSI_VD_DTYPE reg value = 0x3e

modify TSKIP_CNT frome 0x1D to 0x6 or 0x00 ： video still abnormal

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Honle,

Thank you for the information, Indirect page port 0 DSI_STATUS (0x28) is shown as 0x5, so there seems to be an EoT error.

The possible cause of the EoT error is incorrect skip programming since Indirect DSI register 0x5 = 0x32 indicated as reset, and the value shared above is incorrect.

Based on the PCLK (83MHz) and 4 lanes on your configuration,

83 MHz = (F_DSI*4)/12

0.083 GHz = (F_DSI*4)/12

F_DSI = 0.249 GHz

TSKIP_CNT = Round (65*f_DSI-5) = 11 which means you need to program 0x16 to indirect register 0x05, not 0x6 or 0x00.

Best,

Josh

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

F_PCLK = 27.88mhz（920*505*60）

F_DSI = 83.62mhz = 0.08362 ghz

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

Can 941 be configured to display MIPI input images (active video data 800 * 480) through internal timing generation (HSW/HFP/HBP)

0 Honle Zhao 4 months ago in reply to Josh Baik

Intellectual 590 points

Currently the bridge IC LT7911D MIPI DSI TX clock is configured to synchronous mode with the pixel clk according to TI 941 spec, but since it is a DP-to-MIPI protocol bridge IC, there still has asynchronous clock/logic inside it when packetizing the pixel data stream and sync timing into MIPI DSI protocol. It has small probability that will lead to the Hsync timing variation +/- 1 pixel clk unit if TI 941 just using the DPI-type timing packets and pixel clock derived from DSI clock, which symptom is same as what we have observed on TI 926 HSYNC/DE output pin when issue occurred.

Considering current situtation, we would like to get TI team's help to confirm below items:
1. Is there any configuration in TI 941 or TI 926 to regeneate new H/V SYNC timing independently instead of by referring to the HSS/VSS/HSE/VSE packets sent from MIPI source?
2. Is there any registers within TI 941 or TI 926 that could indicate the actual input video timing(Htotal, or Hblanking or HFP/HBP width)? or any registers that could indicate the video timing variation ?
We can try to do software workaround if we could get such kind of info from TI SerDes registers.

0 Josh Baik 4 months ago in reply to Honle Zhao

TI__Mastermind 22986 points

Hi Honle,

Please discard my wrong calculation of Tskip. Apologies it.

I have reviewed the schematic again and have some feedback. Since you selected External Reference Clock Mode on MODE_SEL1 (#4), you must match the frequency with the desired DSI clock, not 25MHz for the external clock shown in the schematic. Please see the requirements in the app note.