- Master controls switches and slave controls LEDs and LCD.
- Master writes to slave over I2C. Slave does not need to write to master.
- Switch rows are inputs & columns are outputs. (Or inverse?)
On boot, we will have the slave (LED controller) listen for an initial request from the master (switch controller) over I2C to ensure that both are communicating correctly. The slave should blink in a special pattern following receipt of the initial request to prove that a connection has been established (if the slave controls the LCD we could also blink the LCD screen). The master will not proceed until it has received a response.
Bitmask using a byte: Upper 3 bits as action: 000 Lower 5 bits as data: 00000 Event Bits 8-6: 111 -> Master in Error State 101 -> Reset Game 001 -> Toggle LED in Data 010 - > Boot 011 -> Game Win Data Bits 5-1
| # | Master | I2C | Slave |
|---|---|---|---|
| 1 | Reset game. GOTO 2. | 101XXXXX | Reset game. GOTO 2. |
| 2 | Get input. GOTO 3. | 001XXXXX | Display output. GOTO 3. |
| 3 | Is Win? | Check for avaliable I2C. | |
| 3a | Yes. Notify. GOTO 1. | 101 | Inform user (blink). GOTO 1. |
| 3b | No. GOTO 2. | GOTO 2. |
Error states deviate from this control flow.
AVR-GCC compiles with
-fno-exceptionsso we have to implement our own form of error handling.
- To use debug code, compile with
-DDEBUG