J7EXPA01EVM: Unable to use i2c communication

min.junlong

Part Number: J7EXPA01EVM
Other Parts Discussed in Thread: J784S4XEVM, TDA4VH

Tool/software:

Hi Ti team，

I am currently using the board J784S4XEVM+J7EXPA01EVM. (The 12V power supply is provided on the J19 port of the J7EXPA01EVM board.)

Referring to the following I2C communication table information, the relevant i2c devices cannot be read correctly.

Here are my steps and the corresponding log output：

Fullscreen debug.txt Download

root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdetect -y 8
Warning: Can't use SMBus Quick Write command, will skip some addresses
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                                                 
10:                                                 
20:                                                 
30: -- -- -- -- -- -- -- --                         
40:                                                 
50: -- -- 52 -- -- -- -- -- -- -- -- -- -- -- -- -- 
60:                                                 
70:                                                 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdump -y 8 0x3d
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
10: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
30: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
40: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
50: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
90: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
a0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
root@j784s4-evm:~# 
root@j784s4-evm:~#                  
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdump -y 8 0x30
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
10: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
30: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
40: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
50: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
90: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
a0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~#                  
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdump -y 8 0x32
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
10: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
20: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
30: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
40: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
50: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
60: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
70: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
80: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
90: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
a0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
b0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
c0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
d0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
e0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
f0: XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX    XXXXXXXXXXXXXXXX
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdump -y 8 0x52
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
40: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
60: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff    ................
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~# i2cdump -y 8 0x18
No size specified (using byte-data access)
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 30 00 33 48 00 03 01 28 fe 1e 11 7f 7f f0 0f 00    0.3H.??(???????.
10: 00 00 80 00 00 20 18 f1 61 00 c0 00 00 10 00 00    ..?.. ??a.?..?..
20: 00 80 00 00 00 04 00 00 77 77 44 44 00 00 00 00    .?...?..wwDD....
30: 40 00 09 04 00 00 00 00 00 00 00 00 00 00 00 00    @.??............
40: 00 00 00 00 00 00 00 00 00 00 00 00 e4 00 00 00    ............?...
50: 10 c0 21 00 00 00 00 00 00 00 00 00 00 00 00 00    ??!.............
60: 00 00 00 00 00 88 00 00 00 00 a0 15 00 00 00 00    .....?....??....
70: 00 00 25 00 00 00 00 00 00 10 e4 00 00 00 00 02    ..%......??....?
80: 00 00 00 0f 00 00 90 00 00 00 00 00 00 80 00 00    ...?..?......?..
90: 32 e3 64 01 00 00 00 00 00 00 20 20 20 20 20 0b    2?d?......     ?
a0: 10 0b 0a 09 09 10 00 00 00 00 00 00 00 00 00 00    ??????..........
b0: 04 a7 5d 00 00 00 00 00 00 00 00 00 00 00 00 00    ??].............
c0: 15 01 2b fa 0b 12 20 13 10 11 02 00 f8 00 00 00    ??+??? ????.?...
d0: d2 1f 1a 1f 21 26 22 00 01 20 00 00 00 00 00 00    ????!&".? ......
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 5f 55 42 39 37 31 00 00 00 00 00 00 00 00 00 00    _UB971..........
root@j784s4-evm:~# 
root@j784s4-evm:~# 
root@j784s4-evm:~#

5 months ago

0 Neehar Sawant 5 months ago

TI__Mastermind 19470 points

Hi,

Which device/devices are you trying to communicate with?

Additionally, can you confirm if you are using Linux + RTOS?

Thanks,

Neehar

0 min.junlong 5 months ago in reply to Neehar Sawant

Prodigy 216 points

Hi,

Just like my screenshot above:I tried to use TDA4VH to communicate with the device on the J7EXPA01EVM board via I2C.The following devices are used to attempt communication.(Deserializer chip:DS90UB9702_0 --- 0x3D, DS90UB9702_1 --- 0x30, DS90UB9702_2 --- 0x32; EEPROM:CAT24C256WI --- 0x52; and Serializer chip: DS90UB971 --- 0x18). The result is that only the serializer chip can be accessed normally, and other devices cannot access it.

0 Neehar Sawant 5 months ago in reply to min.junlong

TI__Mastermind 19470 points

Hi,

Sorry for the delay, I have assigned your thread to the expert who can assist with your issue.

Thanks,

Neehar

0 Keerthy J 5 months ago in reply to Neehar Sawant

TI__Guru**** 162950 points

Hello,

Can you please run the below command and share us the exact instance of i2c bus that you want to try here?

'dmesg | grep i2c'

Also please share the screenshot in English.

Which exact I2C bus instance are you trying to check?

- Keerthy

+1 min.junlong 5 months ago in reply to Keerthy J

Prodigy 216 points

Hi Keerthy,

I have solved the problem. The board needs to control the reset pin, which is in reset by default. The fpd-link is now working properly and can get a video stream.

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J7EXPA01EVM: Unable to use i2c communication