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ADS54J60: problem driving this chip using 32 bit SPI controller.

Layne Jakahi
Intellectual 820 points

Part Number: ADS54J60

I was trying to communicate with 24 bit SPI ADS54J60 with a 32 bit SPI controller, but have been stuck so far.

I tried writing 8 dummy bits following the address bit and then the real 8 bits value.  Also I tried writing real data following the address bit followed by 8 dummy bits. None of this tries seems to succeed since when I read the register back, it shows all ‘0'.  

Can anybody shine some light here?

Thanks in advance,

Layne

  • 0
    TI__Guru* 91947 points

    Layne,

    I am going to try this in the lab today. Does the controller send CS low on the rising or falling edge of clock? I am assuming this signal goes low for 32 clock cycles then goes high? Can you send a diagram showing the timing you are using? To make things easy, instead of trying to do writes and reads, can you monitor power to the device or board, then write a power down command to see if power goes down? Do you have the sample clock and SYSREF present when attempting the SPI writes? These clock signals are required for SPI to operate. 

    Regards,

    Jim

  • 0 in reply to jim s
    TI__Guru* 91947 points

    Layne,

    I did a 32 bit write today with no problem. I just added 8 writes of "0" to the beginning of a normal write cycle with CS held low for these additional 8 clock cycles.

    Regards,

    Jim

  • 0 in reply to jim s
    Intellectual 820 points

    Hi Jim

    We are going to try it today but I think that you are correct in your previous response about the Sample Clock and SYSREF.  I didnt realize that these signals are necessary for SPI transactions.  We had connected the power to the demoboard and jumpered the SPI lines to one of our production cards.  I thought that the SPI transactions would have worked.

    If it still doesnt work, I will restore the demo board and try again.

    thanks for your assistance in this.  

       

  • 0 in reply to Layne Jakahi
    Intellectual 820 points
    Hi, Jim,

    Are you saying that when writing, put eight '0's in front of everything, I mean before the W/R, M, P, CH bit? If so, how about the read operation?

    thanks
  • 0 in reply to Layne Jakahi
    Intellectual 820 points
    Hi Jim
    We are going to try your Power Down suggestion. However, can you elaborate more on "MONITOR POWER TO THE DEVICE"? How do we monitor the amount of current draw? I could'nt find any series resistors on the power supply pins of the ADC where we could put an Ammeter. Furthermore, configuring the PDN pin as an output does not indicate that ADC is in PowerDown mode. When the PDN is configured as an output, it indicates a fast overrange of channel A (whatever that means).
  • 0 in reply to Layne Jakahi
    TI__Guru* 91947 points

    Fullscreen ADS54Jxx_ANALOG.txt Download 
    Write
0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0
1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1	0	0	0	0	0	0	1	1	A15	A15	A14	A14	A13	A13	A12	A12	A11	A11	A10	A10	A9	A9	A8	A8	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	A7	A7	A6	A6	A5	A5	A4	A4	A3	A3	A2	A2	A1	A1	A0	A0	D7	D7	D6	D6	D5	D5	D4	D4	D3	D3	D2	D2	D1	D1	D0	D0	0
2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1
4	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
5	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
6	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
7	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1

Read
0	0	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0	1	0
1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1	0	0	0	0	0	0	1	1	A15	A15	A14	A14	A13	A13	A12	A12	A11	A11	A10	A10	A9	A9	A8	A8	0	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	A7	A7	A6	A6	A5	A5	A4	A4	A3	A3	A2	A2	A1	A1	A0	A0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	D7	D7	D6	D6	D5	D5	D4	D4	D3	D3	D2	D2	D1	D1	D0	D0	0
3	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1
4	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
5	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
6	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
7	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1	1
    Layne,

    I power our EVM with a bench 5V power supply that has a current meter. I watch the total current go down when I sleep the ADC. The attached file is what the FTD USB-to-SPI uses for writing the SPI signals to the ADC. The format is as follows:

    Row 0 - Clock

    Row 1- Address/Data

    Row 2 - Not used

    Row 3 - Chip select

    Row 4 - Row 7 - Not used

    You will notice I added 8 extra writes in the write section of this file. The bottom rows are used during a read cycle, which was not modified.

    Regards,

    Jim