Now studying #BL602 SPI ... Can't wait to get #PineCone driving ST7789 with #LVGL!
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
#BL602 SPI ... Uses UART for DMA? 
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
...Aha it's a Copy-Paste Bug
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
#BL602 uses the new SPI Pin Names ... No more MOSI and MISO 
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
...Wait it's still using the old terms. Should be renamed as "Controller" and "Peripheral", according to the guidelines:
https://www.oshwa.org/a-resolution-to-redefine-spi-signal-names/
Raspberry Pi Pico also uses the old SPI terms
#BL602 SPI Registers are remarkably similar to I2C Registers ... So I can reuse my I2C code for SPI
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
#BL602 SPI Register Fields look similar to I2C too
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
Yep #BL602 SPI is copy pasta from I2C ... Even the Register Address. Very nice!
https://github.com/bouffalolab/bl_docs/tree/main/BL602_RM/en
We'll let #BL602 talk simple SPI to BME280 first ... Before talking seriously to ST7789
https://cdn.sparkfun.com/assets/learn_tutorials/4/1/9/BST-BME280_DS001-10.pdf
#BL602 SPI DMA ... Lets you specify a Linked List of Transmit / Receive operations ... That will be executed by the DMA Controller
https://github.com/lupyuen/bl_iot_sdk/blob/master/components/hal_drv/bl602_hal/hal_spi.c#L115
#BL602 SPI DMA uses simple Interrupt Handlers .... Simpler than I2C! Let's experiment with SPI DMA on BME280
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L749-L794
#BL602 SPI DMA is used by AliOS VFS file system ... Which is bundled with the BL602 IoT SDK
https://pine64.github.io/bl602-docs/Components/Middleware/vfs/vfs.html
...But #BL602 SPI HAL doesn't implement all AliOS SPI Functions
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L368
Nope #BL602 it's a trap! Should call "vfs_spi_init_fullname" to init the SPI port
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L504-L571
Another #BL602 trap! "vfs_spi_init_fullname" doesn't return the SPI Device ... It passes the SPI Device to AliOS! Let's create our own function to init the SPI Port without AliOS
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L504-L571
#BL602 SPI Data Transfer needs a "void *" parameter ... Which is cast to an "spi_ioc_transfer_t" ... That belongs to AliOS 
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L464-L502
Good Sunday Morning #PineCone #BL602 @PINE64 ... And #BME280 on SPI! Yep this looks right
https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L49-L70
#BL602 SPI Transmit and Receive ... Hope this works
https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L72-L102
Our #BL602 SPI program hangs when doing data transfer
https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c
#BL602 SPI DMA Transfer is hanging inside "hal_spi_dma_trans" ... According to the debug log
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L472-L510
"hal_spi_dma_trans" hangs while doing #BL602 SPI DMA transfer because it's waiting for a FreeRTOS Event Group ... Which is supposed to be signalled by the DMA Interrupt Handler. Let's comment out the waiting and see what happens...
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L285-L348
Commented out the waiting for #BL602 SPI DMA ... Yep no more hanging ... But no SPI Data received. Interrupt Counters show that DMA Interrupts weren't triggered.
The plot thickens ... Just like my chicken soup
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L285-L353
These 2 #BL602 SPI Functions are begging me to call them ... Phew this SPI HAL is confusing
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L405
#BL602 SPI Transmit seems OK but not SPI Receive ... After calling "hal_spi_init"
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L826-L876
#BL602 SPI DMA uses a Linked List of DMA requests ... Let's dump the DMA Linked List and verify the SPI Transmit and Receive requests
https://github.com/lupyuen/bl_iot_sdk/blob/spi/components/hal_drv/bl602_hal/hal_spi.c#L160-L199
Aha #BL602 SPI DMA is now Transmitting AND Receiving! The SPI Mode was incorrect ... Got confused between the AliOS docs and the BL602 implementation 
Received SPI Data is garbage though
https://github.com/lupyuen/bl_iot_sdk/blob/spi/customer_app/sdk_app_spi/sdk_app_spi/demo.c#L49-L67
#BL602 SPI Functions are the same as AliOS ... Time to practice my Chinese reading skills
https://help.aliyun.com/document_detail/161063.html?spm=a2c4g.11186623.6.576.391045c4bGoNKS