📄 mastuart.asm
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;====================================================================
;
; Author : ADI - Apps
;
; Date : October 2003
;
; File : MASTuart.asm
;
; Hardware ; ADuC842/ADuC843
;
; Description : This Program transmits the numbers 1-10 in binary
; form continuously down the SPI serial port.
; After the transmission of each byte the incoming
; byte is saved in order between internal RAM
; addresses 40h and 50h.
;
; After the 16 bytes have been writen into memory
; the program outputs the received data up the UART
; where it can be viewed using Hyperterminal.
;
; An SPI slave program can be run on a second ADuC832
; to communicate with this master code.
; The Slave program (SLAVuart.asm in the SPI\SLAVE
; directory) should be started after the master
; program (MASTuart.asm) but within the time delay
; of 5s in order that the slave program is
; synchronised by the first outputted clock of the
; master.
;
; The clock is outputted at sclock (pin 26)
; The data is outputted at sdata/MOSI (pin 27)
; The data is inputted at MISO (pin 14)
;====================================================================
;
$MOD842 ;Use 8052 predefined Symbols
LED EQU P3.4
FLAG BIT 00H
;____________________________________________________________________
; BEGINNING OF CODE
CSEG
ORG 0000H
JMP MAIN
;____________________________________________________________________
; SPI INTERRUPT ROUTINE
ORG 003BH
SETB P3.5 ; set the SS bit after transmission
CLR FLAG ; Clear flag to leave loop
MOV @R1, SPIDAT ; move input into memory
INC R1 ; increment memory location so new
; data is stored in new address
CJNE R1, #50H, CONT ; reset memory location to 40h when
; memory location reaches 50h saving
; 16 bytes of data
CALL SNDUART ; send the data up the UART
CONT: RETI
;____________________________________________________________________
; MAIN PROGRAM
ORG 0060H ; Start code at address above interrupts
MAIN: ; Main program
MOV T3CON,#083h
MOV T3FD,#02Dh
MOV SCON,#052h
MOV SPICON,#037h ; Initialise SPICON to have
; -bitrate=fosc/64
; -CPHA=1
; -CPOL=0, sclk idling low
; -master mode select
; -Enable SPI serial port
MOV IEIP2, #01h ; Enable SPI interrrupt
SETB EA ; Enable interrupts
MOV R1, #40h ; initialise R1 to 40 to store the
; input data from memory location 40
MOV R0, #00H ; initialise R0 to 0 to start
; transmissions from 1
; Delay the output of data by 2.0s in order that the slave program
; can be easily synchronised with the master program.
MOV A, #200
CALL DELAY
TRNSMT:
INC R0
CLR P3.5 ; clear the SS bit during transmission
MOV SPIDAT, R0 ; transmit the current value on R0
SETB FLAG ; set flag so that we wait here until
; the spi interrupt routine clears
; the FLAG
JB FLAG, $ ; stay here until flag is cleared
; by interrupt
; check if R0 is equal to 10. If so the number 10 has been
; transmitted and we should reset R0 to 0 to start transmission
; from 1 again
MOV A, R0
CJNE A, #0AH, TRNSMT ; if R0 is not 10, jump to TRNSMT
MOV R0, #00H ; if R0=10 make R0=0 & jump to TRNSMT
JMP TRNSMT
; Transmit the values in locations 40h->50h up the UART wait for
; 5 seconds and then transmit and receive values to/from the slave
; again down the SPI port.
SNDUART:
CPL LED ;CPL LED with each transmission
MOV DPTR, #TITLE
CALL SENDSTRING ; write title block on screen
MOV R1, #40h ; move value at address 40 into R2
MOV A, @R1
MOV R2, A
NEXT: ; Put new value on a new line
MOV A, #10 ; Transmit a linefeed (= ASCII 10)
CALL SENDCHAR
MOV A, #13 ;Transmit a carriage return (=ASCII 13)
CALL SENDCHAR
MOV A, R2 ; Transmit R2 i.e. value @ address R1
CALL SENDVAL
INC R1 ; Increment address
MOV A, @R1
MOV R2, A ; R2 holds the value @ addrR1
MOV A, R1 ; Check if at address 50h
CJNE A, #50h, NEXT ; if not jump to Next
JMP WAIT2S ; if so wait 2s and repeat
WAIT2S: MOV A, #200 ; wait 2s before sending down the
; SPI port again for ease of viewing
; on screen and to allow the slave
; synchronise itself with the master
CALL DELAY
MOV R1, #40h ; store new inputs at address 40h again
RETI
;____________________________________________________________________
; SENDSTRING
SENDSTRING: ; sends ASCII string to UART starting at location
; DPTR and ending with a null (0) value
PUSH ACC
PUSH B
CLR A
MOV B,A
IO0010: MOV A,B
INC B
MOVC A,@A+DPTR
JZ IO0020
CALL SENDCHAR
JMP IO0010
IO0020: POP B
POP ACC
RET
;____________________________________________________________________
; SENDCHAR
SENDCHAR: ; sends ASCII value contained in A to UART
JNB TI,$ ; wait til present char gone
CLR TI ; must clear TI
MOV SBUF,A
RET
;____________________________________________________________________
; SENDVAL
SENDVAL: ; converts the hex value of A into two ASCII chars,
; and then spits these two characters up the UART.
; does not change the value of A.
PUSH ACC
SWAP A
CALL HEX2ASCII
CALL SENDCHAR ; send high nibble
POP ACC
PUSH ACC
CALL HEX2ASCII
CALL SENDCHAR ; send low nibble
POP ACC
RET
;____________________________________________________________________
; HEX2ASCII
HEX2ASCII: ; converts A into the hex character representing the
; value of A's least significant nibble
ANL A,#00Fh
CJNE A,#00Ah,$+3
JC IO0030
ADD A,#007h
IO0030: ADD A,#'0'
RET
;____________________________________________________________________
; DELAY
DELAY: ; Delays by 10ms * A
; 100mSec based on 2.097152MHZ
; Core Clock
; i.e. default ADuC842 Clock
MOV R3,A ; Acc holds delay variable
DLY0: MOV R4,#01Bh ; Set up delay loop0
DLY1: MOV R5,#0FFh ; Set up delay loop1
DJNZ R5,$ ; Dec R2 until R2 is zero
DJNZ R4,DLY1 ; Dec R1 & Jump DLY1 until R1 is 0
DJNZ R3,DLY0 ; Dec R0 & Jump DLY0 until R0 is 0
RET ; Return from subroutine
;____________________________________________________________________
TITLE: DB 10,10,13,'____________________________________',10,13
DB 'Analog Devices MicroConverter ADuC842',10,13
DB ' SPI MASTER Demo Routine',10,13
DB ' Data Stored in Memory in Hex Form',10,13,0
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