Part Number: DS92LX1622
Tool/software: TI C/C++ Compiler
HiI'm trying to use DS92LX1621/DS92LX1622 pair in camera mode. i am using below circuit to connect to DS92LX1622 chip via I2C to my HOST.at first i tied CAD pin to GND with 0ohm resistor and i used "110 0000" ID to assess the chip on HOST side the problem was that DS92LX1622 do not acknowledge the I2C packet frames.(investigated via Oscilloscope)then i changed the RID to 2.0K and used "110 0001" ID on my I2c_master controller , now it works fine and i can easily read/write DS92LX1622 internal registers.why it is like this?
Have you verified that the I2C control is using the 8 bit or 7 bit addressing scheme based on your system SW? For example with setting RID = GND, try I2C addresses of 0x60 or 0xC0 based on 8bit or 7 bit convention?
Also can you send the scope shots?
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In reply to Casey McCrea:
thanks for the answer
i am using 7 bit addressing scheme so for RID=GND i use "110 0000" to access DS92LX1622
here are two scope shots:
RID=2 Kohm ID:"110 0001" Ack: OK (writing "E0" ro register "27h" of DS92LX1622)
RID=GND ID:"110 0000" Ack: NOT valid
In reply to hsvz vz:
This is a strange issue - is it happening on multiple boards or just one?
unfortunately, I do not have another board to test this on it. I do not think it is related to the hardware because I can read/write the internal registers successfully. maybe there should be more considerations when you use RID=GND (e.g t2c timings,....).
I checked a new 1622 Chip and assembled a new PCB and the same problem exists:
I investigated that a weird thing is happening when RID : GND: the chip does not ACK packet sent to ID "11000000" but it ACK the packet sent to ID"11000010" (which it is supposed to work when RID=2Kohm) !!!
here are two scop shots:
RID =GND ,M/S=H ,PDB:High ID: "11000000"
RID =GND ,M/S=H ,PDB:High ID: "11000010"
btw here is my chip marking:
and my schematic:
What state are the S1 switches in? Have you tried changing between the two modes for M/S?
Casey McCreaWhat state are the S1 switches in?
PDB switch : open=> PDB : High
M/S switch : open => M/S: High
BISTEN switch : Close=> BISTEN : low
Casey McCreaHave you tried changing between the two modes for M/S?
yes, nothing changed.
This issue is quite strange and the device in question part of a legacy portfolio so it may take some time to investigate on this. We will check to see if we can find an eval kit for this device to do some testing on our side. Please expect a follow up in ~ 1 week
I tried this on the DS92LX1622 EVK: https://www.ti.com/tool/LX16EVK01
It is working as expected on that HW. With CAD = GND, the address 0x60 is working:
Is there anything else on this I2C bus which may be influencing the result?
thanks a million for the answer and the test you done.
no there is no other I2C device on the I2C bus and only one Host is connected (a STM32F4 discovery board as Master I2C)
could you please answer these about the EVK and your test?
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