We tried to link 2 DE2 boards together each connected to a seperate desktop computer. The goal was to write something in the Altera monitor terminal on one desktop and have it show up in the terminal of the other.
The code we ended up with didn't work and I'd be thankful if someone could read through it and see why it doesn't.
This was the code used:
.text
.global _start
_start:
movia sp, 0x007FFFFC # Max stack value
movia r6, 0x10001000 # Default address for the data register of JTAG
movia r7, 0x10001010 # Default address for the data register of the serial port
.macro PUSH reg
subi sp, sp, 4
stw \reg, 0(sp)
.endm
.macro POP reg
ldw \reg, 0(sp)
addi sp, sp, 4
.endm
MAIN_LOOP:
call READ_JTAG
call READ_SERIAL
br MAIN_LOOP
READ_JTAG:
# Read data from the JTAG port
ldwio r4, 0(r6)
andi r8, r4, 0x8000
beq r8, r0, END_PUT
andi r5, r4, 0x00ff
PUSH r31
call WRITE_JTAG
call WRITE_SERIAL
POP r31
ret
WRITE_JTAG:
# Write data to the JTAG port
ldwio r4, 4(r6)
andhi r4, r4, 0xffff
beq r4, r0, END_PUT
stwio r5, 0(r6)
ret
READ_SERIAL:# Read data from the serial port
ldwio r3, 0(r7)
andi r8, r3, 0x8000
beq r8, r0, END_PUT
andi r5, r3, 0x00ff
PUSH r31
call WRITE_JTAG
POP r31
ret
WRITE_SERIAL:
# Write data to the serial port
ldwio r3, 4(r7)
andhi r3, r3, 0xffff
beq r3, r0, END_PUT
stwio r5, 0(r7)
ret
END_PUT:
ret
.end
