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Simon Richter da0f228cc7 changed the protocol used to talk to the PRU. PRU now uses both datalines
2021-05-08 16:48:47 +02:00
.idea changed the protocol used to talk to the PRU. PRU now uses both datalines 2021-05-08 16:48:47 +02:00
.gitignore add a first version of the led pru driver 2021-04-10 12:28:43 +02:00
AM335x_PRU.cmd add a first version of the led pru driver 2021-04-10 12:28:43 +02:00
ll_led_drv.c changed the protocol used to talk to the PRU. PRU now uses both datalines 2021-05-08 16:48:47 +02:00
Makefile add a first test sending data to the ws2812 from host 2021-05-02 19:16:52 +02:00
README.md changed the protocol used to talk to the PRU. PRU now uses both datalines 2021-05-08 16:48:47 +02:00
resource_table_empty.h add a first version of the led pru driver 2021-04-10 12:28:43 +02:00

README.md

Looping Louie PRU firmware

This contains the PRU firmware for the leds and light barriers.
Shared memory is used for communication between the PRUs and the Host CPU.
The LED driver runs on PRU0, PRU1 runs the light barrier code.

Memory layout

The shared memory starts at address 0x10000 (PRU) and 0x4A310000 (Host) and has a size of 12KiB.

The first 16 bytes are used as a "management block". Those 16 bytes are split into two 8 byte blocks. The first one is used for PRU0, and the second one for PRU1.

0 1 2 3 4 5 6 7
ready waitFrame frameReady reserved reserved reserved reserved reserved
ready EventFlag lbStatus switchState reserved reserved reserved reserved

Description:

Flag Set by Description
ready PRU PRU is up and running
waitFrame PRU PRU waits for a frame
ONLY when this flag is set, the Host is allowed to write to the framebuffer
frameReady Host / PRU Host wrote a frame and wants the PRU to push it
Cleared by PRU
eventFlag PRU The PRU found a event on one of the light barriers
lbStatus PRU The status of the light barriers as a bitfield
(MSB: Player 7, LSB: Player 0)
switchState PRU The state of the on/off switch
(0 = Off, 1 = On)

Resources

AM335x Technical Referecne Manual:
https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf