Lup Yuen Lee 李立源 @lupyuen@qoto.org

#BL602 #SPI Unsolved Mystery ... BL602 must be configured for SPI Phase 1 to talk to #LoRa SX1276 ... But SX1276 actually uses SPI Phase 0! 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/lora/customer_app/sdk_app_lora/sdk_app_lora/sx1276-board.c#L112-L137

Transmit and Receive #SPI Data on #RISCV #BL602 ... Piece of kueh! 🍰

https://github.com/lupyuen/bl_iot_sdk/blob/lora/customer_app/sdk_app_lora/sdk_app_lora/sx1276.c#L245-L286

How #PineCone #BL602 @PINE64 renders a photo on #ST7789 over #SPI

https://lupyuen.github.io/articles/display#display-image-on-st7789

#ST7789 Display will let us flip it, reverse it ... Here's how we do the #SPI thang on #BL602

https://lupyuen.github.io/articles/display#set-display-orientation

#BL602 #SPI ... Now writing about the 4 fixes I made ... 1️⃣ SPI Data Pins are flipped 2️⃣ SPI Phase should be 1 (though it behaves like 0) 3️⃣ Doing SPI Chip Select ourselves 4️⃣ Pin 0 switches on WiFi LED. Thanks for bearing with this long thread on #PineCone @PINE64 🙏

https://lupyuen.github.io/articles/spi

#PineCone #BL602 @ThePine64 tested OK with #BME280 over #SPI ... Here's the wiring that doesn't light up the WiFi LED 💡

https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L76

#BL602 #SPI Phase 1 ... Looks suspiciously like Phase 0 🤔

#PineCone #BL602 #SPI Unsolved Mysteries ... 1️⃣ Why are the SPI Data Pins flipped? 2️⃣ Why does Pin 0 light up the WiFi LED? 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L54-L115

Here's how we control #BL602 #SPI Chip Select Pin ourselves ... Using plain old BL602 GPIO

https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L47-L128

Nope #BL602 #SPI HAL can't control Chip Select Pin by #GPIO ... Because it has already configured the pin for SPI Port earlier ... Let's control the pin ourselves 👋

https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L98-L122

Nope #BL602 still receiving garbage from BME280 ... Let's do the #SPI Logic Analyser!

https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L70-L114

Sounds impossible... But #Arm's #SWD Protocol (to flash and debug firmware) runs just fine on #RaspberryPi's #SPI port... No need to bang out bits slowly and unreliably over GPIO! It's the reason why #PineTime fans @PINE64 can debug firmware with #VSCode today. Hmmm if only somebody had discovered this much earlier... 🤔 https://medium.com/@ly.lee/openocd-on-raspberry-pi-better-with-swd-on-spi-7dea9caeb590?source=friends_link&sk=df399bfd913d3e262447d28aa5af6b63