Astro-Pi AVR assembly and framebuffer driver now available

[jdb]

As people are now starting to receive boards, the software is now available for download and tinkering.

https://github.com/raspberrypi/rpi-sense

There are two main components in this repository:
- Linux Kernel framebuffer driver for easy access to the LED matrix
- Source code for the Atmel assembly routines that drive the LED matrix and scan the joystick buttons.

[panik]

Can't wait to get my hands on an Astro-Pi HAT! I'm aware it’s not RPF's intention for the ATtiny88 to be reprogrammable by the end-user, but let's not have that stop us from doing it anyway. Thanks for making the code available!

At what frequency is the ATtiny88 running, and what are the fuse settings? Is the AVR RESET pin connected to GPIO pin 25?

The factory default is that it runs off the internal 8MHz clock with CKDIV8 fuse bit enabled and therefore at 1MHz, and RESET to pin 25 considering the reference to @kcuzner's linuxspi avrdude in the README, but that's just guessing.

There are references to the individual components here: https://www.raspberrypi.org/astro-pi-tech-specs/ which is great, but will there be schematics for the full HAT?

[ShiftPlusOne]

I'm aware it’s not RPF's intention for the ATtiny88 to be reprogrammable by the end-user, but let's not have that stop us from doing it anyway.

Indeed, that was one of the first things tested .

I don't know which pin reset is connected off the top of my head, but yes, it's whatever the linuxspi option in avrdude expects.

The clock is 8MHz. Fuse settings are default with CKDIV8 unset.

Don't know what the plans for the schematics are.

[panik]

OK thanks, probably pin 25 then. There wasn't room for an external crystal?

We'll patiently wait.

[ShiftPlusOne]

Nope, I don't think the lack of crystal was down to lack of space.

[panik]

I should have just asked if there was an external crystal or not, to make sure. Fair enough, this works too. Thanks!