Lup Yuen Lee 李立源 @lupyuen@qoto.org

To conserve battery power, #LoRa Sensors don't always listen for incoming packets ... They listen for a few seconds then go back to sleep. 😴 LoRa Receive Timeout is the last thing we shall implement for #BL602

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c#L207-L215

Back to our #BL602 Stack Trace ... Yep the Correct Stack Trace is indeed lurking behind our (unhelpful) Exception Stack Trace ... How shall we show the Correct Stack Trace beyond the Emptiness? 🤔

https://gist.github.com/lupyuen/5ddbcdd1054c775521291c3d114f6cee

Here's how we fixed the #BL602 Exception for #LoRa Channel Activity Detection ... Always init Stack Variables! 🙏

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c#L127-L143

Answer: "radio_events" contains Undefined Fields ... Because it was allocated on the Stack! Lesson Learnt: ALWAYS Init Stack Variables! 🙏

https://github.com/apache/mynewt-core/blob/master/apps/loraping/src/main.c#L215-L233

Quiz: What's wrong with this C code? 🤔 ... I'm soooo upset I missed this simple bug 🙄

https://github.com/apache/mynewt-core/blob/master/apps/loraping/src/main.c#L215-L233

Below the #BL602 Exception Handler Stack ... Is another Stack! ... Does this Stack contain the Stack Trace that we need? 🤔

https://gist.github.com/lupyuen/5ddbcdd1054c775521291c3d114f6cee

Here are the #BL602 Stacks for the Foreground RTOS Task, Background Task and Exception Handler ... Let's see what's wrong with the Exception Stack

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c#L469-L488

Let's dump the #BL602 Stack with this function ... And figure out why our Exception Stack Trace doesn't look right

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c#L469-L488

#BL602 Stack Trace always shows the Current Stack ... Let's show the stack before hitting the #RISCV Exception

https://github.com/bouffalolab/bl_iot_sdk/blob/master/components/bl602/freertos_riscv_ram/panic/panic_c.c#L75-L98

Deciphering the #BL602 Stack Trace Hieroglyphics ... There must be a way to get the Stack Frame before our #RISCV Exception 🤔

https://github.com/bouffalolab/bl_iot_sdk/blob/master/components/bl602/freertos_riscv_ram/panic/panic_c.c#L6-L7

So "Tech Influencer" is a thing now? 🤔 ... My followers will get so frustrated by my super long and convoluted posts 😂

Oops #BL602 needs us to "make clean ; make" to fix up the Stack Frame Pointers ... Now BL602 Stack Trace points to the "ebreak" instruction ... Which belongs to the #RISCV Exception Handler 🙄

https://github.com/lupyuen/bl_iot_sdk/releases/tag/v7.0.1

#BL602 shows Stack Trace when CONFIG_ENABLE_FP=1 ... But the addresses don't make sense ... They belong to the code that's dumping the Stack Trace 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/proj_config.mk#L40-L42

Here's the #BL602 Exception Handler ... Seems capable of showing the #RISCV Stack Trace 🤔

https://github.com/bouffalolab/bl_iot_sdk/blob/master/components/hal_drv/bl602_hal/bl_irq.c#L316-L341

#BL602 Stack Trace Hieroglyphics ... Can we use this to dump the Stack Trace for our #RISCV Exception? 🤔

https://github.com/bouffalolab/bl_iot_sdk/blob/master/components/bl602/freertos_riscv_ram/panic/panic_c.c#L6-L7

Can #BL602 show the Stack Trace for this #RISCV Exception? ... Let's find out 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c

Never clear the #BL602 GPIO Interrupt Status! 🚧 ... This suppresses subsequent GPIO Interrupts 😲 ... We can now receive multiple #LoRa Packets yay!

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/sx1276-board.c#L402-L433

Let's disable #LoRa Channel Activity Detection for now ... #BL602 receives first LoRa Packet ... But not the second packet 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c

Enabled #BL602 GPIO Interrupt Handler for #LoRa SX1276 ... And BL602 hits a #RISCV Exception ... At an invalid Program Address 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/demo.c

Reconnected #PineCone #BL602 @PINE64 ... To #LoRa SX1276 pins DIO0 to DIO3 ... For testing our GPIO interrupt handler

https://github.com/lupyuen/bl_iot_sdk/blob/lorarecv/customer_app/sdk_app_lora/sdk_app_lora/sx1276.h