Hi all,
I have to port a working LoRa project from STM32WL55JC (3.3V) to STM32WLE5CC. First besides the JC (BGA) has more pins thatn the E5CC (QFN), anything else should be the same (expect maiy EXTI which te project does not use).
Now my the issue: The SUBGHZ / LoRa stack is being initialized, no errors no locks, interrupts occur and indicate that any Tx is complete. The internal SPI communcation between STM32 core and the SUBGHZ block is fine. I can read and write any register with no issues.2
But there is no RF signal at all comming out, neider on low nor on high power output. (checked with a decent spectrum analyzer).
I must admit that there is some more difference between the two boards:
+ The WL55JC board gets 3.3V voltage on all VDDxx inputs
+ The WL5ECC board gets 1.8V and some 3.3V from a clean LDO
The wiring on the WL5ECC:
VDD: 1.8V
VDDSMPS: 1.8V
VDDRF1V55: is 1.55V from internal buck (verified OK)
VDDRF: 1.8V
VDDPA: 3.3V (to get max. power)
VDDA: 3.3V (to be able to use VREFBUF)
HSE/SUBGHZ is clocked from an external 32 MHz TXCO.
One problem is of course to due to the limited pins of the QFN WLE5CC I only route some
SUBGHZ debug signals to the output pins.
+ HSE32RDY to PA10. This one is constant low. (I switch system clock to HSE32 at boot and the core and all perihperals run fine with this clock derived from 32 MHZ TXCO -> PLL -> 48MHz chain. so I assume HSE32 is working)
+ RF-DTB1 first low, turns high (1,8V) after Tx reported to have been succesfull
+ RF-SMPSRDY goes from high (1,8V9 to low after boot (I guess this is correct because SMPS is stable 1.55V)
I cannot put out more. But also strange is that VR_PA never gets activated. This line is 48kOhms measured to ground and always stays at 0V.
Any ideas what I'm doing wrong? Anything to check/try/test?
