AD5940 FIFO threshold interrupt triggered when FIFO is empty

Hi,

Could you check if fifo_cfg.FIFOThresh  set to the required value?

Could you ensure that the flag is cleared after each assertion? (AD5940_INTCClrFlag(AFEINTSRC_DATAFIFOTHRESH);)

Hi Akila,

This is the debug output that I've obtained after configuring AD5940 to measure transients, see my comments in parentheses.

Configuring FIFO...
REG_AFE_CMDDATACON has value 0x0489
REG_AFE_DATAFIFOTHRES has value 0x3e80000 (Corresponds to fifo_cfg.FIFOThresh value of 1000)
REG_AFE_FIFOCON has value 0x6800
FIFO threshold register is 0x03e80000

(Interrupt triggered here)
FIFO count is 0
Interrupted with flags: 0x02008000
(Cleared with AD5940_INTCClrFlag(AFEINTSRC_DATAFIFOTHRESH))
Interrupt flags after clearing: 0x00008000.
End of Sequence

(Then code proceeds onto normal measurements)
bMeasureTransient is false
FIFO threshold register is 0x00050000
FIFO count is 0
Interrupted with flags: 0x00000000
Interrupt flags after clearing: 0x00000000

It seems that the transient measurement ended immediately. Also the normal measurements seem to be broken as well (interrupted with all 0 interrupt flags).

I suspect this might be a sequencer programming issue? How would you suggest I debug the sequencer?

Best,
Simon

Hi,

Could you tell which parameter you are watching:

*pCount 

or

FifoCnt 

or

AD5940_FIFOGetCnt()

Also could you tell the value of NumOfData?

Hi Akila,

I have been watching output from AD5940_FIFOGetCnt(), it returns 0 when the interrupt is triggered.

The value of NumOfData was set to -1 for non-stop operation.

Hi,

While running the ChronoAmp example, do you get the desired output on the terminal?

Hi Akira,

Sadly no, since *pCount = FifoCnt, which is 0. So nothing is printed out.

However, the Amperometric example works well without issues.