PIC I/O Board Pin Layout  ver 2.3  6/04/01

The I/O configuration of the PIC chip is generally:
	RA -- digital and analog inputs
	RB -- digital outputs
	RC -- digital inputs and Locator signal I/O

					      PIC name & pin --  header pins
Inputs:

 1 battery level;		(analog  x01)	RA0/AN0	   2	  R1 (- opamp)
 								  R2 (+ opamp)
 1 battery charge;		(analog  x02)	RA1/AN1	   3	  R3 (- opamp)
								  R4 (+ opamp)

 1 PIR heat/motion detector	(digital x04)	RA2	   4	  L1
 1 locator signal strength;	(analog  x08)	RA3/AN3	   5	  L2

 1 sonar ping pulse;		(digital x80)	RB7	  28	  L8

 1 serial locator data;		(capture x02)	RC1/CCP2  12	  L4

 4 bumper switches;     RF	(digital x01)	RC0	  11	  L14
 			LF	(digital x08)	RC3	  14	  L16
			RR	(digital x10)	RC4	  15	  L20
			LR	(digital x20)	RC5	  16	  L18

    Total: 6 binary bits, 1 serial data bit, 3 8-bit analog.


Outputs:

 2 bits steering --	Left	 (digital x01)	RB0	  21	  R8  (740x buf)
			Right	 (digital x02)	RB1	  22	  R6  (740x buf)

 4 bits drive motor --	Fwd low  (digital x04)	RB2	  23	  R10 (740x buf)
 			Fwd med  (digital x08)	RB3	  24	  R12 (740x buf)
			Bkw low	 (digital x10)	RB4	  25	  R14 (740x buf)
			Bkw med  (digital x20)	RB5	  26	  R16 (740x buf)

 1 serial locator signal;	 (compare x04)	RC2/CCP1  13	  L3

    Total: 6 binary bits, 1 serial data bit.


TINI Communication pins:

 2 serial RX/TX to TINI host	(serial)	RC6/TX	  17	  --
						RC7/RX	  18	  --

    Total: 2 serial data bits.


This uses 19 of the 22 available I/O pins on the PIC,
    leaving 3 digital I/O bits available for expansion:
 1 digital I/O or counter;			RA4/TOC1   6	  L12
 1 digital I/O;					RA5	   7	  R2
 1 digital I/O with interrupt			RB6	  27	  L10

The remaining pins are:
						MCLR(+V)   1
						OSC1,2	   9,10	  L6 (clock out)
						Vss(gnd)   8,19	  odd pins
						Vdd(+5)	  20
    Note: R9 and R11 to Power Card are connected to steering switch.


Host Communication Packet layout

Status Input (PIC to HOST), 8 bytes --

 B0 -- 1 byte of stream syncronization pattern data;

 B1 -- 1 byte of binary switch status;
 	b0 -- (available)
 	b1 -- (available)
 	b2 -- RF collision
 	b3 -- LF collision
 	b4 -- RR collision
 	b5 -- LR collision
 	b6 -- PIR sensor
 	b7 -- (available)

 B2  -- 1 byte of locator signal data;
 	As received from CCP2 input.

 B3 -- 1 byte of locator signal strength;
 	From AN3 A->D convertor.

 B4 -- 1 byte of battery level data;
 	As received from AN0 A->D convertor.
 
 B5 -- 1 byte of battery charge data;
 	As received from AN1 A->D convertor.
 
 B6 -- 1 byte sonar ping pulse time;
 	Counted from RB7 input.

 B7 -- auxiliary;
 	For expansion.


Control Output (HOST to PIC), 5 bytes --

 B0 -- 1 byte of stream syncronization pattern data (not stored in PIC buffer);	

 B1 -- 1 byte of binary control signal;
  	b0 -- steer left
 	b1 -- steer right
	b2 -- drive FF
 	b3 -- drive FS
 	b4 -- drive BF
 	b5 -- drive BS
  	b6 -- (reserved)
 	b7 -- (reserved)
	
 B2 -- 1 byte of locator signal data;
 	To be transmitted via the CCP1 output.

 B3,4 -- 2 byte auxiliary;
 	For expansion.