DAC63204: From 3-wire SPI, Trouble unlocking registers for write and setting into 4 wire SPI

Garrett Sos

Part Number: DAC63204

1) power up device (I am using the EVM card without the USB host - the host won't recognize the eval software. Pulled all the host related jumpers)

2) try to unlock chip and set to 4 wire SPI. It does not seem like the chip even notices SPI.

I have had it working for hours on 4-wire writing and reading channels but then it stops recognizing SPI. That was with loose wires everywhere. Now that I have everything cleaned up and firmly attached it won't go again. I think somehow I got it to start again but only by some bad random SPI transfer? I have tried 2 EVM eval boards.

Here is what I think is needed (below), As read back by a SPI monitor. Like I said, I did get it into 4 wire mode twice, and used SPI reliably for many hours, but a power cycle hosed it.

And how does the chip "automatically" detect the SPI protocol? I have tried clock rates from 1.25M to 312.5K Hz

I am at wits end.... thanks for any help.

Here is an example waveform:

over 1 year ago

0 Garrett Sos over 1 year ago

Prodigy 30 points

For reference, here is a screen capture showing two other SPI operating in both directions properly. The DAC63204 chip select is the red trace.

0 Katlynne Jones over 1 year ago in reply to Garrett Sos

TI__Mastermind 33588 points

Hi Garrett,

It's harder to tell from the zoomed out (100us/div) screenshots, but are you following the timing requirements? For example, CS needs to go low at least 18ns before the first SCLK falling edge. It looks pretty close based on your first screenshot. Same with the last SCLK falling edge to the CS rising edge. It looks like those are happening pretty much at the same time, but the device requires at least 10ns.

Please double check that you're meeting all of the timing requirements. You can also send a more zoomed in screenshot of a single write sequence and I can help verify.

What VDD are you connecting to the DAC?

Best,

Katlynne Jones