Hi,
We are working with AFE4490 on a custom made board. Everything goes great: read and write on any register, the pleth signal, TIA gain, RC values, Tx supply with 3V or 5 V etc.
The only issue is we cannot write on control2 register, in particular to modify TX_REF, but the remaining bits cannot be set neither. ie, we always read 000000000000000000000000 value (default reset value) and measure 0.75 V on tx_ref pin using:
-> 3.3V or 5V supply on Tx_ctrl_sup and led_drv_sup pins.
-> 3.3 on rx_dig_sup and rx_ana_sup pins.
We do can set I_max to 75 mA or 150 mA by changing LED_RANGE, but cannot select 200 mA, 100 mA or 50 mA, because TX_REF is always 00.
Power supply is regulated using tps61120 and battery operated.
Every other register seems to be set without problems. I've read the forum but nobody's got the same problem. Do you wonder why this could be happening? could be a protected register by mistake?
Thanks
Leonardo
