Tool/software:
Hi, there ,
We use afe4950 as out afe in our ppg liked scenario. and we have enable the DRE mode.
now we encount a problem with the fifo data，
we use THE AFE to driver out TOSA, which is made of a LED,and capture the current of the ROSA,which is made of pd.
between the TOSA and ROSA is our fiber sensor. to acquire the Vibration signal.
In some situation, when we disconnect the fiber sensor between the tosa and rosa. the fifo read out always stay different ,even though IOFFDAC_AACM_READ_LOOP1 goes back to the same . I mean that while sensor is disconnected from the tosa and rosa 。 there should be no current running into the TIA. and the same IOFFDAC_AACM_READ_LOOP1 indicated that the DAC_LED inject the same current to the TIA. my question is
1) why is the fifo data changed after we reconnect and disconnect the sensor from the system
2) based on the issue 1, we can see a step when the fifo readout reached 0X000000 and quickly jumped to 0xffffff. which is really unreasonable
3) it seems that we have mistake the sign-extension bits in DRE mode, but we cannot fix the code.
4) we have print the BIT23-21 of the fifo readout , we can see 0x0,0X1 0X2 0X3 0X4 0X5 0X6 0X7 ,while in table 7-9 just define 0B000 0B111 0B001 0B110
in out application，the sensor wont be disconnect from the TOSA and ROSA , so we dont need to enable DAC_AMB。 enable or disable the DAC_AMB wont do anything good to the jump step,
thank you
