TI-H: ti92 link port


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TI-H: ti92 link port




hi,
i am working on an io expander for my ti92, i 've found lots of things
for hardware but the hardest part is still the software. How can i set
io wires.
i wanna do manal input/output (i set this wire to +5V and this one to 0V
i wait 10ms and ....).
i 've found this in fargo doc :
---------------------------------------------
:RW [60000E]
    <.......0|........> = set red output, if direct port access enabled
    <......1.|........> = set white output, if direct port access
enabled
    <.....2..|........> = read red output
    <....3...|........> = read white output
    <.6......|........> = enable direct port access
    <........|76543210> = read a byte from the receive buffer (1 byte
buffer)
    <........|76543210> = write a byte to the transmit buffer (1 byte
buffer)
---------------------------------------------
this in sound drivers :
------------------------------------------------
sound:
        move.w          #$2700,sr               ;disable interrupts for
                                                ;smoother sound
        move.b          #00,($60000e)           ;turn off red & white
wires
        or.w            #$0c00,($60000e)         ;turn them on
        move.l          d6,-(a7)                ;save freq
-------------------------------------------------
i don't really understand how this work, if someone could explain to me
that would be nice ...

i have done this :
----------------------------------------
        move.w         #%0000000000000000,($60000e)           ;turn off
red & white wires
        WriteStr
#5,#30,#4,step1                                         ; show "red and
white wire to ground"
        jsr                  userlib::idle_loop
        move.w          #%0000001100000000,($60000e)           ;turn off
red & white wires
        WriteStr
#5,#60,#4,step2                                         ; show "red and
white wires to +5v"
        jsr                 userlib::idle_loop
        jsr                 doorsos::reset_link

rts
;exits the program
-----------------------------------------
this crash my calc and i don't even get the second message ...

i am working on a ti92+ but want to make a program which'll work on all
ti92 so any informations, explainations .... is really welcome.

thanx

thomas
sarfata@altern.org