; SPItstS0.asm
; SLAVE Rev 0
; Demonstrates SPI connection between 2 PICs
; Master sends data (a counter), Slave receives and outputs to LEDs
; on PORTB
	list p=16F876

	#include "p16F876.inc"
	_CONFIG 
	_CP_OFF 
	_DEBUG_OFF 
	_WRT_ENABLE_OFF
	_CPD_OFF
	_LVP_OFF
	_BODEN_OFF
	_PWRTE_ON
	_XT_OSC
	_WDT_OFF

#define CS 0x20 ; PORTA,5 (HW SS pin)

	ORG 0X00
	nop 		; FOR ICD
; Set up the SPI Support
	BANKSEL TRISA ; BANK 1
	movlw 	CS 	; Chip Select pin
	movwf 	TRISA 	; is in input mode
	movlw 	0x06 	; Turn Off A/D mode for at least the
	movwf 	ADCON1	 ; Chip Select pin (all Digital mode)
; Set up output port
	BANKSEL TRISB 	; BANK 1
	movlw 	0x00 	; Configure all PORTB pins
	movwf 	TRISB 	; to be in output mode
; Set up the SPI
	BANKSEL TRISC 	; BANK 1
	movlw 	0x18 	; SCK is input (Slave), SDI is input,
	movwf 	TRISC 	; SDO is output, all others output
	movlw 	0x40 	; Mode 1,1 SPI with
	movwf 	SSPSTAT 	; middle of output time sampling
	BANKSEL SSPCON 	; BANK 0
	movlw 	0x34 	; Mode 1,1 SPI Slave Mode, /SS Required
	movwf 	SSPCON 	; SSP is on
; Here is the SPI Slave Code. Again, it looks complex, but it is a complete example
; and not just a segment of code.

Chk4Dat 
	movlw SSPSTAT 	; Indirectly test
	movwf FSR 	; a register by loading FSR
	btfss INDF,BF 	; Here is the test
	goto Skip_ND 	; New data, do a transfer (below
RX_Data 
	BANKSEL SSPBUF 	; BANK 0
	movf SSPBUF,W 	; put in SSPBUF into W
	BANKSEL PORTB 	; BANK 0
	movwf PORTB 	; Show the results on PORTB
DoAgain
; Optional customer code can go here
	goto Chk4Dat 	; Receive Next Byte
	end