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ADS131A04: Problems with initialization

Heimo Gaicher2
Prodigy 30 points
Part Number: ADS131A04


Hi,

i am struggling with initialization of ADC.

I use 24Bits, no Hammingcode, no CRC. I did this steps and i mean that until point 3 all is OK.

step Command 1.Byte 2.Byte 3.Byte Response on MISO
1 NULL  0x00 0x00 0x00 0xFF04
2 UNLOCK 0x06 0x55 0x00 0x0655
3 WAKEUP 0x00 0x33 0x00 0x0033
4 WREG 0x0F 0x0F 0x00 ???

But after step 4 i got different values on MISO pin.

Are this steps right?

  • 0
    TI__Guru* 98995 points

    Heimo,

    Out of curiosity, what are you getting for the WREG response? In the table, you're only showing "??".

    For the initialization of the device, I often look at the method shown in the datasheet in the flow diagram. There is an initialization setup shown on page 79 of the datasheet.

    In that case, the NULL response at startup showing ready (FF04) isn't shown, but that's what the Receive Ready Word? box is doing. The sequence starts with the UNLOCK command and then goes into the WREG to program the configuration of the device.

    After the configuration is programmed, a WREG 0F 0F to enable all of the ADCs. After that, a WAKEUP command is sent. If you have an EVM, this is basically how the startup script sets up the device in the initial configuration. Note, I think the WAKEUP command is sent just a bit earlier in the EVM script, but it shouldn't affect the configuration.

    Joseph Wu