HP Vectra Technical Reference Manual page 192

set_B041 proc near
push
cx save working set of regs
push bx
push ax
xor cx,cx
loop 64k times (if necessary)
mov bh,led_data load data for loop
mov
b~hp8041--set-1ed
load command
cli ints must be off for this loop
set_B04'_'0:
in al,hp8041--status-port get status and see if 8041
test al,hp8041--ibf--"Jask
input buffer if full
loopnz set_804'_'0
loop if it is
mov al,bl
load command and
out hp8041_data-port,al ship it out
cmp
bh,al did we output both bytes
je set_8041--.20 yes, skip out
mov
bl,bh set up for next iteration
xor cx,cx
jmp
short set_804'_'
0 loop
,..
set_8041--.20:
sti CHANGE this to restore
int flag
to
previous state
instead of on (if needed)
pop
ax
pop bx
pop cx
ret
set_8041
endp
Table 5.17 lists the 8041 Controller Commands. These commands are categorized as READ,
SNGL, or DBL. READ commands cause the 8041 Controller to place the indicated data byte in it's
output buffer, input port 60H, to be read by the 80286. SNGL commands are commands written
to output port 64H. DBL byte commands are written to output port 64H with the following data
byte being written to output port 60H.
Keyboard 183