; The following "$" commands must be included in every module

$NOMOD51 ; Omit assembler predefined registers.

$INCLUDE(reg515.inc) ; Include 515/535 microcontroller definitions.

NAME SERIAL ; Optional parameter; if no name is provided,

; the filename will be used by default.

PUBLIC SERINIT, SEROUT, ALERT; Lets other modules access this section of code

; from "public domain" utilizing the EXTRN command.

EXTRN CODE (LCDOUT)

; Makes subroutines LCDINIT and LCDOUT in the

; lcd.a51 module available to module main.a51 .

MR1BDAT EQU 00010011B

MR2BDAT EQU 00000111B ;Set stop bit length = 1

;Put registers in memory spaces

ACR EQU 04H ;Auxiliary Control Register

MR1B EQU 08H ;Mode Register B (1-receiver 2-transmitter)

SRB EQU 09H ;Channel B Status Register

CSRB EQU 09H ;Clock Select Register B

CRB EQU 0AH ;Channel A Command Register

THRB EQU 0BH ;Tx holding register

;***********************************************************************************

SERIAL SEGMENT CODE ; Reserve RAM space for the generic code

; segment, MAIN. The name segment name is referred

; to by the following RSEG directive.

RSEG SERIAL ; Selects the MAIN code segement, and makes it

; "active" at this point in assembled code.

; The selected segment remains "active" until

; a different segment is specified.

USING 0 ; Indicates to the assembler that register

; bank 0 will be used, but does not actually

; select register bank 0 .

SERINIT:

MOV A,#01010000B ;Do from this command, down to 00010000

COM_B_RESET:

MOV P2,#CRB

MOVX @R1,A

ADD A,#-16 ;Subtracts 1 from the upper nibble; loop until = 0000

;0101=Reset channel A interrupt

;0011=Reset transmitter.

;0010=Reset receiver.

;0001=Reset MR pointer. Points MR pointer to MR1.

;0000=No command, exit loop.

JNZ COM_B_RESET ;If the first 4 bits don't equal 0000 jump back to COM_B_RESET.

COM_B_SETUP:

MOV P2,#MR1B ;Points Mode Register 1B to Port 2

MOV A,#MR1BDAT ;Initializes MR1B receiver first in order to

MOVX @R1,A ;initialize MR2B next for transmission.

MOV A,#MR2BDAT ;Stores mode register parameters in acc

MOVX @R1,A ;Move MR2BDAT into MR2B

MOV P2,#ACR ;

MOV A,#80H ;Points 80H into ACR in Port 2

MOVX @R1,A ;Baud Rate Generator Set Select = 1

MOV P2,#CSRB ;Set BAUD rate to 1.8kHz

MOV A,#01000100B

MOVX @R1,A

MOV A,#00000101B ;Points data bits for CRB into Acc

MOV P2,#CRB ;Points CRB into Port 2

MOVX @R1,A ;Points data bits into CRB at Port 2

RET ;Enables the COM B - transmitter and reciever

ALERT:

MOV B,#20 ;WILL TRANSMIT THE NUMBER OF TIMES OF THE

;NUMBER STORED IN B

SEROUT:

MOV A,@R1

;POP ACC ;PUTS THE ID# INTO THE ACC

;MOV A,#37H ;Test data to be sent to the transmitter

SEROUTB:

MOV P2,#SRB

PUSH ACC ; SAVE CHAR for later use

SOUTB1:

MOVX A,@R1 ;Point external Port 2 to Acc

JNB ACC.2,SOUTB1 ;Loop until SRB-bit 2 (TXrdy) is ready to transmit

POP ACC

MOV P2,#THRB ;Send out the serial bit stored

MOVX @R1,A

DJNZ B,SEROUT

RET

END