Disabling UP9600 hack for use with C128
#1
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The UP9600 hack does not work on the C128 computers.  By default, the WiModem is shipped with this hack is enabled.  To disable it, you need to cut one jumper.  There are actually 3 jumpers that control the UP9600 hack, but only one interferes with the C128's SRQ line used for burst mode, which will prevent the IEC bus from working while in C128 mode with 1571 & 1581 drives (including the C128DCR).  C64 mode works fine.  Only the C64 can take advantage of the UP9600 hack, which gives you the ability to run the C64 at 9600 baud.

Cut the trace that is between the two jumper pads shown below.  To restore the hack, solder between the two pads.  You can reach these pads even with the OLED screen.  If you feel that this is too difficult for you to do, then return the board to me and I will ship you a version with all of the pads cut to disable the UP9600 hack completely.


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#2
Gah....I just learned about this when I tried to use my brand new WiModem.

What functionality (if any) will I lose if I cut that jumper? Confused
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#3
You lose the UP9600 hack support when using a C128 (in C64 mode) with a 1571 or 1581 disk drive.  If you are using a 1541 then you don't need to cut the trace.
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#4
(03-14-2017, 05:50 PM)admin Wrote: You lose the UP9600 hack support when using a C128 with a 1571 or 1581 disk drive.  If you using a 1541 then you don't need to cut the trace.

Sorry I know that, but does that prevent me from connecting above 2400 baud? ie. can I still connect to Commodore Server @ 38400?
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#5
The V1541 driver only works in C64 mode. In C64 mode you don't have to disable the UP9600 hack. The C128 mode is where the problem is.
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#6
Thanks but that still doesn't answer my question.  I want to be able to use WiModem in C128 with C128 terminals.  But I can't load from a 1571.  If I break the jumper, I will be able to use my 1571 and c128 mode, but when I want to use V-1541 will I be limited to 2400baud in this case? If that IS the case, how possible is it to change the jumper with an actual replaceable jumper that I can put on and take off as needed?
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#7
The UP9600 hack works with a C64 (or C128 in C64 mode), it does not work with a C128 in C128 mode. So, yes, would be limited to 2400 baud in C64 mode if you disable the hack. There are two pads there. You could solder wires that lead from those two pads to a toggle switch. The jumper to cut (as shown above) is located slightly under the OLED (if you ordered a WiModem with that option), so you need to be careful when soldering wires so you don't damage the glass display by applying pressure to it by accident. A fine tipped soldering iron at an angle can reach the pads.
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#8
(03-15-2017, 12:13 PM)admin Wrote: The UP9600 hack works with a C64 (or C128 in C64 mode), it does not work with a C128 in C128 mode.  So, yes, would be limited to 2400 baud in C64 mode if you disable the hack.  There are two pads there.  You could solder wires that lead from those two pads to a toggle switch.  The jumper to cut (as shown above) is located slightly under the OLED (if you ordered a WiModem with that option), so you need to be careful when soldering wires so you don't damage the glass display by applying pressure to it by accident.  A fine tipped soldering iron at an angle can reach the pads.

Oh BTW, in case anyone is reading this thread.  You CAN use WiModem in C128 mode at 9600 Baud if loading from a 1541 drive.  I've been using Desterm 2.0 at 9600 baud, works great.
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#9
That's good to know! Does that terminal have a UP9600 driver or is it that the 2MHz machine is fast enough?
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#10
(03-17-2017, 10:36 PM)admin Wrote: That's good to know!  Does that terminal have a UP9600 driver or is it that the 2MHz machine is fast enough?

I'm not sure of that answer.  I can tell you that Desterm allows you to set a baud rate of up to 56K but nothing above 9600 seems to work with the WiModem.
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