We are designing our board with EFR32 microcontroller that runs Zigbee Stack. Due to shortage of supplies we chose 40MHz to replace 38.4MHz clock in reference design. However, when assembled, the board reported that assertion failed in phy.c:1527.
As it is shown in figure above, RFHAL_Init will try to read current HFXO frequency (r0=40000000), then compare with a predefined hardcoded value from FLASH (r3=38400000) . The function will then return 1 when current clock is not 38400000Hz.
I would like to ask do we have to use 38.4MHz oscillator for Zigbee application?