Hello everyone,
I'm developing this wireless sensor:
CC1101 + TPS62730 as power supply at 2,1V
MCU cortexM0
TPS63036 BuckBoost 3,3V DC/DC for battery use (PSM/PWM mode for low power)
accelerometer MEMs that can work up to 2,5V
If TPS62730 is in Bypass mode everything works well (CC1101 in Tx and Rx mode). I have add the control of TPS62730 by mcu output pin to my fimrware now. Looking to the following application note: AN097 - Current Savings in CC254x Using the TPS62730 there is a dedicated pin of CC254x that control ON/BYP pin on TPS62730. CC1101 don't has this pin for ON/BYP
Main question is: when MCU must control the ON/BYP pin in my schematic with CC1101?
a) before write FIFO buffer in TX Mode
b) after write FIFO buffer in TX Mode only during packet trasmission (GDOx_CFG[5:0]=0x06 )
I have try to switch ON TPS62730 before write the FIFO buffer in TX Mode, but CC1101 do not send the packet (case a). I belive using CC1101 @2.1V (TPS 62730 ON mode) do not let to SPI to work correctly if MCU supply is @3.3V, is it right?
If I switch ON TPS after FIFO buffer write command I'm not sure if there is a true power saving during assert of the interrupt packet trasmission (case b)
Second question: how I can estimate (in RX mode) when switch ON TPS62730 if I don't know when packet will arrive?