Hi!
We are working with three AFE4490 connected to same SPI line of a controller, and we have also connected an SD card to the same SPI line of the controller, here the SD Card is working, but the AFE4490 is not working.
As per the data sheet, we checked the following pins, and we got the below voltages, in the respective pins
* VCM = 0.046V
* VG = 0.086
* TX _ REF = 5V
We tried interfacing an external AFE4490(seperate power supply), in the same board. The MOSI is working, but MISO not working. then we disconnected all the MISO line for the 3 AFE4490 in the board, and we connected the external MISO, and it worked.
doubts:
1) Why we are getting different voltages in the VCM / VG/ TX_REF line
2) Why MISO line worked when we connected SD card, but why its not working when we connected external AFE4490
3) Is there any other special configuration required for multiple AFE4490 connection
I have attached the circuit diagram for your reference
Note:- SD CARD circuit is missing, but the SD CARD is connected in the same SPI line.
