Which is super strange because GPIO 4 is supposed to be MISO on #BL604 ... Not MOSI! 🤔

https://lupyuen.github.io/articles/spi#spi-data-pins-are-flipped

GPIO 4 works as MOSI but not GPIO 17 ... What if we connect GPIO 4 to 17? Nope still nothing on the #PineDio Stack ST7789 Display 🤔

@JF discovered this function from #BL604 IoT SDK that swaps MISO and MOSI ... Let's test GLB_Swap_SPI_0_MOSI_With_MISO

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789/pinedio_st7789/demo.c#L53-L75

Yep MISO and MOSI are now swapped! This matches the SPI Pin Definitions in #BL604 Reference Manual ... So from now on we'll always call GLB_Swap_SPI_0_MOSI_With_MISO

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789/pinedio_st7789/demo.c#L53-L75

#BL604 GPIO 17 is now free from the MOSI Curse! But nothing appears on #ST7789 Display 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789/pinedio_st7789/demo.c#L53-L75

Need to verify that our #ST7789 Display is hardwired for "3-line 9bit serial I/F Ⅱ" mode: IM0 = 1, IM1 = 0, IM2 = 1, IM3 = 1 🤔

https://www.rhydolabz.com/documents/33/ST7789.pdf

Let's port moononournation's awesome 9-bit-banging GFX Library to #BL604 ... And compare the SPI Output with a Logic Analyser

https://github.com/moononournation/Arduino_GFX

We run the GFX Library on Linux ... To see the data that will be transmitted to #ST7789 Display

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789_bitbang/test/test.c

#BL604 GFX Library is indeed Bit-Banging 9-bit data to #ST7789 ... But #PineDio Stack Display is still blank 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789_bitbang/pinedio_st7789_bitbang/demo.c

Disabled Logging in #BL604 GFX Library ... SPI Clock looks cleaner now ... But still nothing on #ST7789 Display 🤔

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789_bitbang/pinedio_st7789_bitbang/demo.c

Since our #ST7789 Display doesn't respond to GFX Library 9-Bit Banging ... Maybe our display isn't hardwired for 3-Wire 9-Bit mode? Let's verify IM0 to 3 with the display maker

https://www.rhydolabz.com/documents/33/ST7789.pdf

Porting #Arduino GFX Library to #BL604 wasn't so hard! Just need to map the Arduino API to the BL604 IoT SDK 👍

https://github.com/lupyuen/bl_iot_sdk/blob/3wire/customer_app/pinedio_st7789_bitbang/pinedio_st7789_bitbang/Arduino_SWSPI.c#L37-L43

What's it like to create #OpenSource software for brand new Prototype Hardware ... Like #PineDio Stack BL604? All shall be explained in this article

https://lupyuen.github.io/articles/pinedio?1

Solar Panel @PINE64 ... With hidden treasure inside

https://lupyuen.github.io/articles/pinedio?2

Connecting #PineDio Stack BL604 @PINE64 ... To a super-familiar ST7789 SPI Display

https://lupyuen.github.io/articles/pinedio?3#connect-the-display

#BL604 Blinky Firmware ... Exactly the same as #BL602!

https://lupyuen.github.io/articles/pinedio?4#bl604-blinky

Flashing Firmware to #PineDio Stack #BL604 ... With the same tools as BL602!

https://lupyuen.github.io/articles/pinedio?5#flash-firmware-to-bl604

SPI Bus on #PineDio Stack #BL604 ... Shared by ST7789 Display, LoRa SX1262 and SPI Flash

https://lupyuen.github.io/articles/pinedio?6#bl604-spi

Debugging SPI on BL604 for the @thepine64
#PineDio Stack with @lupyuen : Why are MOSI and MISO swapped? And will GLB_Swap_SPI_0_MOSI_With_MISO() help us?