ADS1247: SPI read isuue

Dave Stevens

Part Number: ADS1247

I'm using an ADS1247 with a PIC32MX530.

The ADS seems to program correctly i.e. I can see the conversion rate change and excitation currents being turned on etc; however I can not read back the registers or get a conversion result.

When I read the ADS the first byte is correct but all subsequent bytes are 0x00.

I have tested by changing the start reg to read back and alter the number of regs to read and always the same result.

Any ideas?

See logic analyser O/P - 12 regs programmed only the first byte 0x0A read correctly.

over 7 years ago

0 Joseph Wu over 7 years ago

TI__Guru* 97465 points

Dave,

Looking at the logic analyzer plot, if the fifth line down from the top is the /CS, then you've raised /CS right after the read command and number of bytes-1 (20 0B). This resets the SPI communication and you won't get the register read from the device.

Joseph Wu

0 Dave Stevens over 7 years ago in reply to Joseph Wu

Prodigy 40 points

Many thanks - After 30 years of doing this you would think I could read the data sheet!

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ADS1247: SPI read isuue