I need some verification or correction on something I came across.
I currently have a display that for some reason have SCL (clock) on the same pin as D/C (data command). I want to use 8 bit 4-line SPI with the built in ST7789VI driver.
I checked the wiring of the pins, and all are connected to the right pins I configure in the software (except I don't define D/C because I already use it as SCL). When I try to display Hello World, only the backlight is on. There seems to be no communication between my controller and the display. I have hooked an oscilloscope to my SCL, MISO, and MOSI pins and the only signal I see is when SPI gets initialized in the setup(). After that, there is no signal.
I have used 8 bit 4 -line SPI with ST7789VI driver successfully before, but that was a different display that had separate SCL and D/C pins.
Thus, I found this unusual with the new display I got. Looks more like a faulty pin configuration build because the ST7789VI library I am using requires the D/C pin.
Thanks for your feedback. I can see why you are confused. I am slightly confused as well thus I am asking for verification.
From my previously working display the pinout did say:
CS, MISO, MOSI, SCK, D/C, RES, IM0, and IM1.
But on this new display it says:
CS, SDA, SDO, SCL (D/CX), RES, IM0, IM1, and IM2.
When I spoke with a rep, they said I can use SDA as MOSI and SDO as MISO since the display supports SPI. Also, in the datasheet for the ST7789VI driver it says SDA is SPI input when IM3 is set HIGH, yet I don't have an IM3.
So, I am asking around if that is a manufacture problem or am I reading this SPI reference incorrectly.
The model pdf appears to have pin labels for a different interface than SPI and makes no sense to me. Contact the company that sold you the new display and ask them for information on pin connections for SPI.
yes, it's not worth listing all the requirements here since my only issue was the SPI pin configuration. The requirements would make it more confusing to others on what my issue was.