Interfacing with GPIO, UART, SPI, I2C etc

[hishi]

Hi Stephen,

I finally got UART_AO_A to work with following instructions.

Instruction of how to fix 2 seconds delay at boot and not working reboot

I was looking for environment that helps me to edit/compile U-boot loader to disable 2 seconds delay at boot time…Cuz I’m completely new to some kernel editing stuff. So I create it and sharing with you guys))) + Bonus is that now $ reboot stuck bug is fixed by created boot-loader and board can reboot as expected The Official instruction doesn’t work for me (there were many errors on different stages) but you should read it to understand the process and where most files and commands were …

Thanks a lot!

[Javier_Vela]

HI,
I had a similar problem. I was connecting Radxa Zero to my custom circuit. My custom cirtuit has the uart connected to ST3232. Radxa didn’t boot. My solution was to put a 10K pulldown resistor in RX, pin 10. After this, Radxa boots.

[SCIFI.radio]

Radxa team, can you please share the procedure for setting up a ST7789 display via SPI?

This would be a great thing to put on the Wiki for the Zero, as a great many of us bought the board with the intention of making small form factor devices with such displays, and so far only a tiny handful of people have managed it at all. I think if you had a clear step by step tutorial it would open the floodgates for sales of the device.

[pratham26]

Can you tell how to configure I2C for DS1307 on radxa zero
things till now done
1> DS1307 is connected to I2C_EE_M3 port on Zero
2> added overlays=meson-g12a-i2c-ee-m3-gpioa-14-gpioa-15 in /boot/uEnv.txt
3> when run sudo i2cdetect -y 3 it scans and return UU in one of address block
also I wanted to connect PCF8574 on I2C bus
I am confused with device trees and overlays please guide me in right direction
Thanks You

[pyzahl]

Hi, may I ask why GPIO pins 12 and 18 are used for SPI in/out – if read this in the link above correctly – vs the “native” (and RP Zer W/RP…) more compatible and as I see also my the design supported pins 19 (MOSI) and 21 (MISO) and 23 (SCLK) pins?

I originally look at this and was happy it fits my old AD converter’s add on hardware.

https://wiki.radxa.com/Zero/hardware/gpio

Is there a way to make pins 19,21,23 work for SPI?

[Stephen]

@Nasca

Please provide one guide to use SPI with PIN #19/21/23.

[pyzahl]

I’d be very happy to find a guide. Just got my armbian up and running from the EMMC as I wanted it.

I have some simply python code hacked to read a multichannel hi precision AD hat (waveshare) via SPI. It all works on a old RP-Zero-W, but this old device it a bit underpowered for the task and to server data via influxdb. I do monitor various analog data channels (reading temperatures from PT1000 sensors on a hot water solar system and a few more channels…) – to ultimately display via grafana. I hope to make this faster and more reliable or less prone to drop outs. (Happy to share if any interest)

[Nasca]

Hi @pyzahl, I have fixed this issuse already, please use this img instead.

[pyzahl]

Cool, many thanks.

Just, wonder as this a whole debian image – what got changed? Kernel/ add on module or overlay?
Or multiple support tools included as. well?

Asking if I could update/patch a running armbian system simply or better go with the new debian?

[pyzahl]

I have it running from SD card for testing. I found overlay for SPI on GPIOH_4-7 via the rsetup util. Good.

Q: what may I use for apt/sources.list for this build to not create chaos/mixups? The setting it came with “deb http://apt.vamrs.com/debian …” is not accessible?

As I need to grab a few extra packages for influxdb, spi, python add ons…

[Nasca]

if you use armbian kernel, you only need to change the overlay, for the dts file, you can refer to this.