;-- --------------------------------------------------------------------------
;--
;-- configuration fuses
;--
;-- --------------------------------------------------------------------------

;-- no code protection             11_11
;-- don't care bit                      x
;-- no data protection                   1
;-- LVP disabled                           0
;-- brownout reset enabled                  1
;-- internal MCLR                            0
;-- power-up delay enabled                      0
;-- watchdog disabled                            0
;-- HS osc                                    0   10 
 

       __CONFIG       0x3fff & _LVP_OFF & _MCLRE_ON & _BODEN_OFF & _PWRTE_OFF & _WDT_OFF & _HS_OSC
;
	PROCESSOR 16F628
;
	#include "p16f628.inc"
;
;----------------------------------------------------------------------------
ENDINT		macro
		goto	EndInt
		endm
	
RETINT		macro
		retfie
		endm	

;Constantes

SPBRG_VAL	EQU	.10		;set baud rate 115200 for 4Mhz clock
V35_BIT_RX	EQU	.3		;PIN Input DATA V35 (PORTB)
V35_BIT_TX	EQU	.0		;PIN Output DATA V35 (PORTA)
;----------------------------------------------------------------------------
;Variables
		CBLOCK	0x20
		ContCTS
		ContWait
		Cont
		V35FlagT
		V35FlagR
		V35Bit
		TmpDeb
		V35RXIndice
		V35Out
		V35BuffIn
		V35BuffOut
		V35_TEMP		;Temporal para Byte recibido por V35
		RS232Buffer			;transmit data buffer (RS232)
		V35Buffer			;Transmit data buffer (V35)
		ENDC
;----------------------------------------------------------------------------
;Macros to select the register bank
; Many bank changes can be optimized when only one STATUS bit changes

Bank0		MACRO			;macro to select data RAM bank 0
		bcf	STATUS,RP0
		ENDM
;-----------------------------------------------------------------------------

org 0x00
;IMPORTANTE: Si el programa pasa de 1 Kb hay que verificar el uso de PCLATH
		clrf    PCLATH		;select program memory page 0
  		goto    Main		;go to beginning of program
;
org 0x04
;NOTA: el programa trabaja solo en el BANK0
InterruptCode:



V35Int:
		bcf	INTCON,INTF
;Output
		movf	V35Out,W
		movwf	PORTA		
;Input 
		movf	PORTB,W
		movwf	V35Bit

;->

		incf	ContWait,F
		btfss	ContWait,4
		goto	V35TX

		bcf	V35Out,2
		clrf	ContCTS
V35TX:
		bcf	STATUS,C
		rrf	RS232Buffer,F
		bcf	V35Out,V35_BIT_TX
		btfsc	STATUS,C
		bsf	V35Out,V35_BIT_TX

;Analiza Bit recibido
V35Input:

		btfss	V35FlagR,0
		goto	V35RXStartBit

V35RX:
		rrf	V35_TEMP,F
		bcf	V35_TEMP,7
		btfsc	V35Bit,V35_BIT_RX
		bsf	V35_TEMP,7

		decfsz	V35RXIndice,F		
		ENDINT

V35Fin:
		clrf	V35FlagR

		movwf	V35Buffer

		bsf	V35FlagT,0

EndInt:
		btfss	PIR1,RCIF	;test RCIF receive interrupt
		goto	RS232TX

		movf	RCREG,W		;get received data
		movwf	RS232Buffer
		bsf	V35Out,V35_BIT_TX

		incf	ContCTS,F
		btfsc	ContCTS,2
		bsf	V35Out,2
		clrf	ContWait
RS232TX:
		btfss	PIR1,TXIF	;test TXIF Transmit interrupt
		RETINT
		btfss	V35FlagT,0
		RETINT
		clrf	V35FlagT
		
		movf	V35Buffer,W
		movwf	TXREG

		RETINT

V35RXStartBit:
		btfss	V35Bit,V35_BIT_RX
		ENDINT				;Lecturó un 0, ignorar
		
		bsf	V35FlagR,0
		movlw	0x08
		movwf	V35RXIndice
		clrf	V35_TEMP
		ENDINT

;============================================================================
; MAIN LOOP
;============================================================================

Main:		


		clrf	PORTA
		clrf	PORTB
		MOVLW	0X07
		MOVWF	CMCON

		Bank1
		clrf	TRISA
		movlw	0xFF
		movwf	TRISB
		bsf	OPTION_REG,INTEDG
		bsf	INTCON,INTE
		Bank0
		call	SetupSerial	;set up serial port and buffers
		Bank0
		bcf	INTCON,INTF
		clrf	PIR1
		bsf	INTCON,GIE		


MainLoop:

		goto	MainLoop



;----------------------------------------------------------------------------
;Set up serial port and buffers.

SetupSerial:	Bank1			;select bank 1
		BSF	TRISB,1
		BSF	TRISB,2
		movlw	SPBRG_VAL	;set baud rate
		movwf	SPBRG
		movlw	0x24		;enable transmission and high baud rate
		movwf	TXSTA
		Bank0			;select bank0
		movlw	0x90		;enable serial port and reception
		movwf	RCSTA

		call	InitV35Buffer	;initialize V35 buffer
		call	InitRS232Buffer	;initialize RS232 buffer

		return

;----------------------------------------------------------------------------
;Circular buffer routines.
;----------------------------------------------------------------------------
;Initialize V35 buffer

InitV35Buffer:	
		movlw	V35Buffer	;take address of transmit buffer
		movwf	V35BuffIn	;and place in transmit start pointer
		movwf	V35BuffOut	;and place in transmit end pointer
		clrf	V35RXIndice
		clrf	V35FlagR
		clrf	V35FlagT
		clrf	V35Out
		clrf	ContCTS
		clrf	ContWait
		clrf	Cont
		
		return

;Initialize RS232 buffer

InitRS232Buffer:	
		clrf 	RS232Buffer
		return

		END