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|
**************************************************************************
*
* Title: Hardware Controller
*
* Objective: CMPEN 472 Homework 5
*
* Revision: V1.0
*
* Date: Feb. 21, 2025
*
* Programmer: Jacob McDonnell
*
* Company: The Pennsylvania State University
* Department of Computer Science and Engineering
*
* Algorithm: Simple Serial I/O, Parallel I/O use, time delay-loop, and PWM control
*
* Register Use: A & B to control LEDS initially, Light Level, current byte, etc
* X & Y to hold the counter in the loop and address of strings and length of string.
*
* Memory Use: RAM Locations from $3000 for data,
* RAM Locations from $3100 for program
*
* Input: Parameters hard-coded in the program - PORTB
* Serial Port for User Input
*
* Output: LED 1 at PORTB bit 4
* LED 2 at PORTB bit 5
* LED 3 at PORTB bit 6
* LED 4 at PORTB bit 7
* Serial Port for String Output
*
* Observation: This program will respond to user input to turn on and off LEDs 1, 2, & 3,
* Dim LED 4 from 100% to 0%, Dim LED 4 from 0% to 100%, and echo user input
* back to the terminal in Type Writer Mode.
*
* Note: ON CSM-12C128 board,
* Switch 1 is at PORTB bit 0, and
* LED 4 is at PORTB bit 7.
*
* Comments: This program is developed and simulated using CodeWarrior
* development software and targeted for Axion
* Manufacturing's CSM-12C128 board running at 24MHz.
*
**************************************************************************
* Parameter Declearation Section
*
* Export Symbols
xdef pgstart ; export 'pgstart' symbol
absentry pgstart ; for assembly entry point
* Symbols and Macros
PORTA equ $0000 ; i/o port A addresses
DDRA equ $0002 ; data direction register for PORTA
PORTB equ $0001 ; i/o port B addresses
DDRB equ $0003 ; data direction register for PORTB
SCIBDH equ $00C8 ; Serial port (SCI) Baud Register H
SCIBDL equ $00C9 ; Serial port (SCI) Baud Register L
SCICR2 equ $00CB ; Serial port (SCI) Control Register 2
SCISR1 equ $00CC ; Serial port (SCI) Status Register 1
SCIDRL equ $00CF ; Serial port (SCI) Data Register
CR equ $0d ; carriage return, ASCII 'Return' key
LF equ $0a ; line feed, ASCII 'next line' character
NULL equ $00 ; NULL Terminator character
**************************************************************************
* Data Section: address used [ $3000 to $30FF ] RAM Memory
*
org $3000 ; Reserved RAM memory starting address
; for Data for CMPEN 472 class
Counter dc.w $0036 ; X register count number for time Delay
; loop for 10 useconds
; The work to calculate this number is in
; the comments for the delay10usec subroutine.
LEVEL dc.b $0005 ; Light Level that the LED should be
buffer ds.b $0010 ; Array of 16 bytes to read a string
dc.b NULL ; NULL terminated
lenBuf dc.w $0010 ; Length of buffer array
buffer2 ds.b $0010 ; Array of 16 bytes for reading and reversal
dc.b NULL ; NULL terminated
lenBuf2 dc.w $0010 ; length of buffer2
badAddr dc.b 'invalid input, address',CR,LF,NULL ; Error message for bad address
badData dc.b 'invalid input, data',CR,LF,NULL ; Error message for bad data
badCom dc.b 'invalid input, command',CR,LF,NULL ; Error message for bad command
* There is a second Data Section at the end of the file.
*
**************************************************************************
* Program Section: address used [ $3100 to $3FFF ] RAM Memory
*
org $3100 ; Program start address, in RAM
pgstart lds #$3100 ; initialize the stack pointer
ldaa #%11110001 ; LED 1,2,3,4 at PORTB bit 4,5,6,7
staa DDRB ; set PORTB bit 4,5,6,7 as output
ldaa #$0C ; Enable SCI port Tx and Rx units
staa SCICR2 ; disable SCI interrupts
ldd #$0001 ; Set SCI Baud Register = $0001 => 1.5M baud at 24MHz (for simulation)
std SCIBDH ; SCI port baud rate change
mainLoop
ldaa #$12
ldab #$CD
ldy #buffer
jsr PrintHexWord
ldx #buffer
ldy lenBuf
jsr Zeros
ldaa #CR
jsr putchar
ldaa #LF
jsr putchar
ldaa #$FF
ldab #$FF
ldy #buffer
jsr PrintDecimalWord
ldx #buffer
ldy lenBuf
jsr Zeros
ldaa #CR
jsr putchar
ldaa #LF
jsr putchar
ldx #Counter
jsr PrintMem
ldx #buffer
ldy lenBuf
jsr Zeros
ldx #buffer
ldy lenBuf
jsr ReadString
ldx #buffer
jsr ReadDecimal
bra mainLoop
ldx #msg ; Load the address of msg into X
jsr WriteString ; Jump to WriteString to output message on serial
ldx #buffer ; Load the address of buffer into X
ldy lenBuf ; Load length of buffer into Y
jsr Zeros ; jump to Zeros to zero out buffer
ldx #buffer ; Reload address of buffer into X
ldy lenBuf ; Load the length of the buffer into Y
jsr ReadString ; Jump to ReadString to read user input into buffer
ldx #buffer ; Reload Address of buffer into X
jsr CheckInput ; Jump to CheckInput to handle user input
bra mainLoop ; Loop back to mainLoop always
TypeWriter ldx #twMsg ; Load Type Writer welcome message address
jsr WriteString ; Jump to WriteString to write message to serial
twReadLoop jsr getchar ; Read Character from Serial
beq twReadLoop ; While Character == 0, branch to twReadLoop
jsr putchar ; Write Character back to terminal
staa PORTB ; Write Character to PORTB
bra twReadLoop ; Branch always to twReadLoop
**************************************************************************
* Subroutine Section: address used [ $3100 to $3FFF ] RAM Memory
*
;*************************************************************************
; CheckInput subroutine
;
; This subroutine will check the input string and match the option.
;
; Input: Address of null terminated string in X.
; Output: No Output, Control flow changed to proper subroutine.
; Registers in use: X for the address of the string, A & B to read characters from
; from the string.
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine will not return a value, it will jump to the proper subroutine
; based on the input given.
;
CheckInput
rts ; Return to caller
;*************************************************************************
; ReadHex subroutine
;
; This subroutine will read an ASCII string of a number in hex and convert it to
; its value.
;
; Input: A memory address in register X.
; Output: The value of the hex number in the Y register, and any errors printed
; to the seriel line. Zero bit is set if error occurs.
; Registers in use: X for the address of the contents and for a buffer while printing,
; D for multiplication, B for the character, Y for output value.
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine will return the value in the Y register, and if an error occurs,
; the Zero bit in the CCR will be set.
;
ReadHex
pshx ; Save X to the stack
pshd ; Save D to the stack
ldy #0 ; Clear Y register
ldab 1,x+ ; Read character from X into B, add 1 to X
cmpb #'$' ; Compare B to '$'
bne rHError ; If B != '$', jump to error, not hex data
rHLoop ldab 1,x+ ; Read Next character from X
beq rHDone ; If B == 0, exit loop
cmpb #' ' ; Compare B to space character
beq rHDone ; If B == ' ', exit loop
cmpb #'0' ; Compare B to '0' character
blt rHError ; If B < '0', bad address, exit loop
cmpb #'9' ; Compare B to '9' character
bhi rHAlpha ; If B > '9', check if 'A'-'F' characters
subb #'0' ; Subtract '0' from B to get true value
pshb ; Save B to the stack
ldd #16 ; load 16 into D
emul ; Multiply Y and D
exg d,y ; Transfer data from D to Y
pulb ; Restore b from the stack
aby ; Add B to Y
bra rHLoop ; Branch always to rHLoop
rHAlpha cmpb #'A' ; Compare B to 'A' character
blt rHError ; If B < 'A', bad address, exit loop
cmpb #'F' ; Compare B to 'F' character
bhi rHError ; If B > 'F', invalid data, error out
subb #'A' ; Subtract 'A' from B to get true value
addb #$A ; Add $A to B to account for offet
pshb ; Save B to the stack
ldd #16 ; load 16 into D
emul ; Multiply Y and D
exg d,y ; Transfer data from D to Y
pulb ; Restore b from the stack
aby ; Add B to Y
bra rHLoop ; Branch always to rHLoop
rHDone clra ; clear A accumulator
tap ; Transfer A into CCR to clear zero bit
puld ; Restore D from the stack
pulx ; Restore X from the stack
rts ; Return to caller
rHError ldx #badAddr ; Load address of bad address string into X
jsr WriteString ; Write string to seriel output
ldaa #4 ; Load 4 into A to set zero bit in CCR
tap ; Transfer A into CCR to set zero bit and warn error
puld ; Restore D from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; ReadDecimal subroutine
;
; This subroutine will read an ASCII string of a number in decimal and convert it to
; its value.
;
; Input: A memory address in register X.
; Output: The value of the number in the Y register, and any errors printed
; to the seriel line. Zero bit is set if error occurs.
; Registers in use: X for the address of the contents and for a buffer while printing,
; D for multiplication, B for the character, Y for output value.
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine will return the value in the Y register, and if an error occurs,
; the Zero bit in the CCR will be set.
;
ReadDecimal
pshx ; Save X to the stack
pshd ; Save D to the stack
ldy #0 ; Clear Y register
dHLoop ldab 1,x+ ; Read Next character from X
beq dHDone ; If B == 0, exit loop
cmpb #' ' ; Compare B to space character
beq dHDone ; If B == ' ', exit loop
cmpb #'0' ; Compare B to '0' character
blt dHError ; If B < '0', bad address, exit loop
cmpb #'9' ; Compare B to '9' character
bhi dHError ; If B > '9', check if 'A'-'F' characters
subb #'0' ; Subtract '0' from B to get true value
pshb ; Save B to the stack
ldd #10 ; load 10 into D
emul ; Multiply Y and D
exg d,y ; Transfer data from D to Y
pulb ; Restore b from the stack
aby ; Add B to Y
bra dHLoop ; Branch always to rHLoop
dHDone clra ; clear A accumulator
tap ; Transfer A into CCR to clear zero bit
puld ; Restore D from the stack
pulx ; Restore X from the stack
rts ; Return to caller
dHError ldx #badAddr ; Load address of bad address string into X
jsr WriteString ; Write string to seriel output
ldaa #4 ; Load 4 into A to set zero bit in CCR
tap ; Transfer A into CCR to set zero bit and warn error
puld ; Restore D from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; PrintMem subroutine
;
; This subroutine will print the address and contents of the given memory location.
;
; Input: A memory address in register X.
; Output: The memory address in Hex and the contents in binary, hex, & decimal
; on the seriel output.
; Registers in use: X for the address of the contents and for a buffer while printing,
; D for the contents of the location, Y for another buffer address while
; reversing strings and printing.
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine requires the seriel console to be setup before calling.
;
PrintMem
pshy ; Save Y to the Stack
pshd ; Save D to the Stack
exg x,d ; Copy Address from X to D to print
ldy #buffer ; Load the address of buffer into Y
jsr PrintHexWord ; Print the Address in Hex
exg d,x ; Copy Address from D to X
ldaa #'=' ; Load the '=' character into A
jsr putchar ; Print the character to the seriel
ldaa #'>' ; Load the '>' character into A
jsr putchar ; Print the character to the seriel
ldd x ; Load data from address in X into D
ldx #buffer ; Load the address of the buffer into X
ldy lenBuf ; Load the length of the buffer into Y
jsr Zeros ; Fill the buffer with Zeros
jsr PrintBinaryWord ; Print the binary word to the seriel
psha ; Save A to the stack
ldaa #' ' ; Load Space character into A
jsr putchar ; Print Space character to the seriel
jsr putchar ; Print Space character to the seriel
pula ; Restore A from the stack
ldy #buffer ; Load the address of the buffer into Y
jsr PrintHexWord ; Prin the hex representation of the word to seriel
psha ; Save A to the stack
ldaa #' ' ; Load Space character into A
jsr putchar ; Print Space character to the seriel
jsr putchar ; Print Space character to the seriel
pula ; Restore A from the stack
ldx #buffer ; Load the address of the buffer into X
ldy lenBuf ; Load the length of the buffer into Y
jsr Zeros ; Fill the buffer with Zeros
ldy #buffer ; Load the address of the buffer into Y
jsr PrintDecimalWord; Prin the decimal representation of the word to seriel
ldaa #CR ; Load the carriage return character into A
jsr putchar ; Print the character to seriel
ldaa #LF ; Load the line feed character into A
jsr putchar ; Print the character to seriel
puld ; Restore D from the stack
puly ; Restore Y from the stack
rts ; Return to caller
;*************************************************************************
; strrev subroutine
;
; This subroutine will reverse a string from one buffer into another.
;
; Input: Address of null terminated string in X, address of a large enough
; buffer in Y.
; Output: The string in X reversed in Y.
; Registers in use: X for the address of the string, Y for the address of the buffer,
; A to read characters from the string.
; Memory locations in use: Memory Address for serial line, address of the string & buffer
;
; Comments: This subroutine will not check that the output buffer is large enough, that
; is the job of the caller.
;
strrev
pshx ; Save X to the stack
pshy ; Save Y to the stack
psha ; Save A to the stack
revLoop ldaa 1,y- ; Load Character from Y into A, decrement Y
beq revDone ; If Character is 0, exit loop
staa 1,x+ ; Save character in address in X, increment X
bra revLoop ; Loop back always
revDone pula ; Restore A from the stack
puly ; Restore Y from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; PrintBinaryWord subroutine
;
; This subroutine will print a given word of data to the serial in binary.
;
; Input: 1 word of data in register D
; Output: Binary representation of the data on the serial console
; Registers in use: X to count the number of bits written, D for the input, A for characters,
; B for the byte being written.
; Memory locations in use: Memory addresses for serial.
;
; Comments: This subroutine requires serial to be setup and putchar subroutine.
;
PrintBinaryWord
pshx ; Save X to the stack
pshd ; Save D (A:B) to the stack
pshb ; Save B to the stack (we want these bits again later)
tab ; Transfer A to B to get upper byte
ldaa #'%' ; Load '%' into A
jsr putchar ; Print '%' to serial to denote binary number
ldx #16 ; Load 16 into X, since we're printing 16 bits
bPrintLoop rolb ; Rotate MSB of B into C of CCR
tpa ; Copy CCR into A
anda #1 ; and A with 1 to get only LSB
adda #'0' ; Add '0' to A to get ASCII Character
jsr putchar ; Print Character A to serial
dbeq X,bPrintDone ; Decrement X and if X == 0, branch to done
cpx #8 ; Compare X to 8 to check if done with upper byte
bne bPrintLoop ; If X != 8, loop to bPrintLoop
pulb ; Restore B from stack to get lower byte
bra bPrintLoop ; Branch back into loop to print lower byte
bPrintDone puld ; Restore D (A:B) from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; PrintHexWord subroutine
;
; This subroutine will print a given word of data to the serial in binary.
;
; Input: 1 word of data in register D, Buffer Address in Y
; Output: Hexadecimal representation of the data on the serial console
; Registers in use: Y for the address of the buffer, X to count the number of bits
; written and for division, D for the input, A for characters.
; Memory locations in use: Memory addresses for serial.
;
; Comments: This subroutine requires serial to be setup and putchar subroutine.
;
PrintHexWord
pshx ; Save X to the stack
pshd ; Save D (A:B) to the stack
pshy ; Save Y to the stack
hPrintLoop ldx #16 ; Load 16 in X for division
idiv ; Divide D / 16 to get Hex Digit
cpx #0 ; Compare X to 0
beq hCheck ; If X == 0, branch to check D is zero
hDNotZero cmpb #$0A ; Compare A to $0A
blt hex10 ; If B < $A, branch to hex10
addb #'A' ; Add 'A' to B to get ASCII Character
subb #$0A ; Subtract $A to adjust characters
stab 1,+y ; Save character from B to Y
exg X,D ; Swap values in X and D
bra hPrintLoop ; loop to hPrintLoop
hex10 addb #'0' ; Add '0' to B to get ASCII Character
stab 1,+y ; Save character from B to Y
exg X,D ; Swap values in X and D
bra hPrintLoop ; Loop to hPrintLoop
hCheck cpd #0 ; Compare D to 0
bne hDNotZero ; If D != 0, branch back to hDNotZero
hPrintDone ldaa #'$' ; Load '$' into
staa 1,+y ; Save '$' into buffer in Y to denote Hex
ldx #buffer2 ; Load the address of buffer2 in X
jsr strrev ; Reverse string in Y in buffer in X
jsr WriteString ; Jump to write string to write the number
ldy lenBuf2 ; Load the length of buffer2 into Y
ldx #buffer2 ; Load the address of buffer2 into X
jsr Zeros ; Fill buffer2 with zeros
puly ; Restore Y from the stack
puld ; Restore D (A:B) from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; PrintDecimalWord subroutine
;
; This subroutine will print a given word of data to the serial in binary.
;
; Input: 1 word of data in register D, Buffer Address in Y
; Output: Decimal representation of the data on the serial console
; Registers in use: Y for the address of the buffer, X to count the number of bits
; written and for division, D for the input, A for characters.
; Memory locations in use: Memory addresses for serial.
;
; Comments: This subroutine requires serial to be setup and putchar subroutine.
;
PrintDecimalWord
pshx ; Save X to the stack
pshd ; Save D (A:B) to the stack
pshy ; Save Y to the stack
dPrintLoop ldx #10 ; Load 10 in X for division
idiv ; Divide D / 10 to get Hex Digit
cpx #0 ; Compare X to 0
beq dCheck ; If X == 0, branch to check D is zero
dDNotZero addb #'0' ; Add '0' to B to get ASCII Character
stab 1,+y ; Save character from B to Y
exg X,D ; Swap values in X and D
bra dPrintLoop ; Loop to hPrintLoop
dCheck cpd #0 ; Compare D to 0
bne dDNotZero ; If D != 0, branch back to hDNotZero
dPrintDone ldx #buffer2 ; Load the address of buffer2 in X
jsr strrev ; Reverse string in Y in buffer in X
jsr WriteString ; Jump to write string to write the number
ldy lenBuf2 ; Load the length of buffer2 into Y
ldx #buffer2 ; Load the address of buffer2 into X
jsr Zeros ; Fill buffer2 with zeros
puly ; Restore Y from the stack
puld ; Restore D (A:B) from the stack
pulx ; Restore X from the stack
rts ; Return to caller
;*************************************************************************
; Zeros subroutine
;
; This subroutine will write zeros to every byte in a given array.
;
; Input: Address of an array in X and its length in Y
; Output: Zeros in every byte of an array.
; Registers in use: X for the address of the array, Y for the length, and A for 0
; Memory locations in use: Memory Address of the array
;
; Comments: This subroutine requires serial to be setup and putchar subroutine.
;
Zeros
psha ; Save A to the Stack
clra ; Clear A
zerosLoop staa 1,x+ ; Load A into byte at X
dbne y,zerosLoop ; Decrement Y and loop if Y != 0
pula ; Restore A from the stack
rts ; Return to caller
;*************************************************************************
; WriteString subroutine
;
; This subroutine will write a given null terminated string to the serial.
;
; Input: Address of null terminated string in X
; Output: Null terminated string written to serial
; Registers in use: X for the address of the string and A for the current byte
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine requires serial to be setup and putchar subroutine.
;
WriteString
psha ; Save A to the stack
writeLoop ldaa 1,x+ ; Load the byte at addr in X, then add 1
beq doneWrite ; if A == 0, branch to doneWrite
jsr putchar ; Jump to putchar to write byte to serial
bra writeLoop ; branch always to writeLoop
doneWrite pula ; restore A from the stack
rts ; return to caller
;*************************************************************************
; ReadString subroutine
;
; This subroutine will read a string from the serial line to a given address.
;
; Input: Address of an array in X
; Output: Null terminated string in the given array
; Registers in use: X for the address of the string Y for the length of the string,
; and A for the current byte
; Memory locations in use: Memory Address for serial line, address of the string
;
; Comments: This subroutine requires serial to be setup and getchar subroutine.
;
ReadString
psha ; Save accumulator A to the stack
pshy ; Save Y to the stack
pshx ; Save X to the stack
readLoop jsr getchar ; Jump to putchar to write byte to serial
beq readLoop ; While A == 0, loop
cmpa #CR ; If A == CR, exit loop
beq doneRead ; Branch to doneRead if A == CR
staa 1,x+ ; Save the byte to the addr in X, then add 1
jsr putchar ; Write Character back to the terminal
dey ; Decrement Y by 1
beq doneRead ; If Y == 0, no more room, stop reading
bra readLoop ; branch always to readLoop
doneRead ldaa #LF ; Load Line Feed into A
jsr putchar ; Write LF to terminal
pulx ; Restore X from the stack
pulY ; Restore Y from the stack
pula ; restore A from the stack
rts ; return to caller
;*************************************************************************
; putchar subroutine
;
; This subroutine writes a single byte to a serial line
;
; Input: A single ASCII byte in accumulator A
; Output: Sends one character to SCI port
; Registers in use: Accumulator A with input byte
; Memory locations in use: SCISR1 and SCIDRL status and data registers
;
putchar brclr SCISR1,#%10000000,putchar ; wait for transmit buffer empty
staa SCIDRL ; send a character
rts ; Return to caller
;*************************************************************************
; putchar subroutine
;
; This subroutine reads one byte from the SCI port
;
; Input: One byte from the SCI port
; Output: One byte in accumulator A
; Registers in use: Accumulator A for output byte
; Memory locations in use: SCISR1 and SCIDRL status and data registers
;
getchar brclr SCISR1,#%00100000,getchar7 ; If no input on SCI port, return 0
ldaa SCIDRL ; Read one byte from SCI port into A
rts ; Return to caller
getchar7 clra ; Set A to 0
rts ; Return to caller
**************************************************************************
* Data Section: address used [ $3100 to $3FFF ] RAM Memory
*
; unknown: string to warn the user of unknown output
unknown dc.b 'Error: Unknown Command',CR,LF,NULL
; twMsg: welcome message when type writer loads
twMsg dc.b 'Welcome to Type Writer, you may type below.',CR,LF
dc.b 'Restart to enter main menu again.',CR,LF,NULL
; msg: this is the main option menu string
msg dc.b 'L1: Turn on LED1',CR,LF
dc.b 'F1: Turn off LED1',CR,LF
dc.b 'L2: Turn on LED2',CR,LF
dc.b 'F2: Turn off LED2',CR,LF
dc.b 'L3: Turn on LED3',CR,LF
dc.b 'F3: Turn off LED3',CR,LF
dc.b 'L4: LED4 goes from 0% light level to 100% light level in 0.4 seconds',CR,LF
dc.b 'F4: LED4 goes from 100% light level to 0% light level in 0.4 seconds',CR,LF
dc.b 'QUIT: Quit menu program, run Type writer program.',CR,LF,NULL
end ; last line of the file
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