ADS7038: data caputured looks earlier

W Z

Part Number: ADS7038
Other Parts Discussed in Thread: TMS320F28386D,

TMS320F28386D connect with Ads7038 using SPID.

In the below picture shows that actually I am sent 0x08 0x10 0x11, but in the logical analyzer shows that the sometimes the data caputured looks earlier.

The send picture shows the detail wrong frame.

The third picture shows the set up, does this problem cause by the setup, the Dupont Line？？

//! Mode 0. Polarity 0, phase 0. Rising edge without delay.
SPI_PROT_POL0PHA0 = 0x0000U,

over 2 years ago

0 Tom Hendrick over 2 years ago

TI__Guru**** 181871 points

Hi WZ, not sure what the issue is at the moment, but the SDI and SDO are out of phase:

DIN (MOSI) is valid on a falling clock, while DOUT (MISO) is valid on a rising SCLK edge. What happens when you change the DIN phase relationship?

0 W Z over 2 years ago in reply to Tom Hendrick

Expert 2370 points

You mean to change the mode?

//! Mode 3. Polarity 1, phase 1. Falling edge with delay.
SPI_PROT_POL1PHA1 = 0x0003U

0 Tom Hendrick over 2 years ago in reply to W Z

TI__Guru**** 181871 points

Mode 2 actually, Pol = 0, Phase = 1.

0 Tom Hendrick over 2 years ago in reply to Tom Hendrick

TI__Guru**** 181871 points

Or would that be mode 1? Different CPU use different terminology. Anyway, CPOL = 0 (SCLK dwells low) and CPHA = 1, read on second active edge.

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ADS7038: data caputured looks earlier