Software Plan - First Run

Minimum specifications:

• Use the existing hardware.
• Run at 4MHz = 1MIPS on the internal RC oscillator to free up two extra pins.
• Servo communications,
  
• Bit bash a one-wire serial communications protocol,
• based on dallas 1-wire bus?
• Bit bash a two wire bus (maybe easier),
• I2C.
• Traditional servo pulse width command.
  
• Each Servo individually addressable,
• 255 unique addresses 0x00 - 0xFE,
  
• one broadcast address 0xFF.
• Servo action - position control,
• PID controller,
• Adjustable P, I and D gains.
• Other controller (LQR?).
  
• Dead band adjustment.
  
• PWM power control for motor.
• Debug LED(s).
• Store configuration in EEPROM (128 bytes),
• Address.
• Controller gains.
• Control limits,
• Position extremes.
• Torque\Current extremes.
  
• Home Position.
  

Optional features:

• Current sensing,
• additional current sensing amp hardware required.
• use additional ADC pin (GP4).
• Constant torque controller.

Design Overview:
At startup:

1. Load the configuration data from EEPROM data memory into RAM.
2. Configure device.
1. GPIO, GP1 and GP2 output (H-bridge).
2. GPIO, GP4 and GP5 (comms).
   
3. ADC, GP0 input (Pot).
   
4. TIMER0 (8bit, 1MHz, prescaler 1,2,4,8,16,32,64,128,256) for PWM.
   
5. TIMER1 (16bit, 1MHz, prescaler 1,2,4,8) for Comms.
   
3. If startup bit START_CONTROL set then initialise control to "home position", else disable motor.
4. Initialise communications protocol, begin listening for address.