ADS131A04: Synchronous Master Mode

Vladimir Nikiforov

Part Number: ADS131A04

Hi all,

I have a question about Synchronous Master Mode. I connect the ADC like in figure 63( M0 pin to GND, ADC NDRDY is connected to DSP NCS).My DSP is in SPI Slave Mode. I would like to configure ADC registers after power up. If I understand correct, it means that I will shift out command word after DSP receive NCS. My question is when the ADC will initiate communication (pull down NDRDY) while ADC is not enabled(not written 0Fh to the ADC_ENA and no new data to pull NDRDY in normal way)?

P.S. I don’t have board(it is in production) and can’t check it by myself….

over 7 years ago

0 Tom Hendrick over 7 years ago

TI__Guru**** 180931 points

Hi Vladimir!

Welcome to our e2e forum! For the ADS131A04 as a Synchronous Master, you can still consider the flow chart (Figure 106) on page 79 of the datasheet. After power up and reset, the device will send you the READY word. It will keep sending that at the default data rate until you queue up the 'Unlock' command. After you send the unlock command, you can configure the registers as you wish, and then send the ADC enable command.

0 Vladimir Nikiforov over 7 years ago in reply to Tom Hendrick

Prodigy 20 points

Thank you for reply.
If I understand correct, default data rate is the same as Tdata from the table 7.10 Timing Requirements: Synchronous Slave Interface Mode

0 Tom Hendrick over 7 years ago in reply to Vladimir Nikiforov

TI__Guru**** 180931 points

Hi Vladimir,

Yes, that is correct.

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ADS131A04: Synchronous Master Mode