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PGA460: PGA460 and PGA460EVM

Yoshifumi Yamaoka
Prodigy 40 points
Part Number: PGA460

Hello, I hve question about URAT communication interval for PGA460 integrated circuit. 

uart speed is 115200 bps.

Now we are doing:

1. Initial parameter setting.

2. Then, make burst-listen, measurement, diag-check and diag-clear.

So, acutal command is 

 cmd 17 08 (burst and listen)

 cmd 5 (measurement results)

cmd  9 4D (check 4Dh diag  register)

cmd  10 4D00 (reset 4Dh diag to zero)

Then, loop those command.

The interval between command to comand is 1ms.

Here is logs example for one loop

[2022-07-07 17:46:50.901] => cmd 0 17 08
[2022-07-07 17:46:50.995] RET: OK
[2022-07-07 17:46:50.995] => cmd 0 5
[2022-07-07 17:46:51.089] RET: 40 0901AC81FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF 87
[2022-07-07 17:46:51.104] => cmd 0 9 4D
[2022-07-07 17:46:51.198] RET: 40 00 BF
[2022-07-07 17:46:51.198] => cmd 0 10 4D00
[2022-07-07 17:46:51.307] RET: OK

In case I makes some loop on this command, then response would stop. It looks like IC does not response timely

[2022-07-07 17:46:54.432] RET: 40 0870E5A4FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF BC
[2022-07-07 17:46:54.447] => cmd 0 9 4D
[2022-07-07 17:46:54.588] RET: 40 00 BF
[2022-07-07 17:46:54.588] => cmdcmd 0 5
[2022-07-07 17:46:54.588]
[2022-07-07 17:46:54.588] ERR: Unknown command
[2022-07-07 17:46:54.588] => cmd 0 04D00
[2022-07-07 17:46:54.588] ERR: Parameters contain non-numeric characters
[2022-07-07 17:46:54.588] => cmd 0 cmd 0 9 cmd 0 5
[2022-07-07 17:46:54.588] ERR: Parameters contain non-numeric characters
[2022-07-07 17:46:54.588] => cmdcmd 0 17 08
[2022-07-07 17:46:54.588]
[2022-07-07 17:46:54.588] ERR: Unknown command
[2022-07-07 17:46:54.588] => cmcmd 0 9 4D

I know, if we added more longer internval time e.g. 200ms, then communication would be okay. But, we pursue the higest speed comnication.

my question is is any requirement (spec) of internal time between sending command. PLease advise .

Also, please advise where we need to check iniside the PGA460 spec about this interval time. 

Rgs

Yoshifumi Yamaoka 

  • 0
    TI__Mastermind 23045 points

    Hello Yamaoka-san,

    Thanks for posting to the Sensing forum!

    Just a quick note on this implementation: 

    "cmd  9 4D (check 4Dh diag  register)

    cmd  10 4D00 (reset 4Dh diag to zero)"

    This register auto clears after a read so there is no need to clear the register after reading it the content will be auto cleared to 0's.

    About your question now: As far as a recommended timing goes there are a couple of recommendations we make in the datasheet you can read these under the UART Interface Command List (pg 38). Some commands take different amounts of time to execute. Such as a burst and listen, so make sure you are mindful of this when working on your timing for your algorithm. 

    Here are some of the recommendations:

    For commands 10 and 22: Wait 60 µs if INIT_GAIN, TVG, THR or P1_GAIN_CTRL or P2_GAIN_CTRL is written to before a read, otherwise wait 3.3 µs for other functions

    For commands 12, 14 16, 23, 24, and 25: Wait 50 µs before issuing a read command

    Section 6.14 contains info on length of other measurements such as a burst and listen or temperature measurements. This will help you decide how much time to allocate between each of those commands listed on this table.

    I hope this is able to covers the instances you were looking at let me know if there are any questions remaining!

    Best,

    Isaac