Karin Maxi Disabled

[pcuser4]

I do not like the flicker and black screen during the reading/formatting/writing. Can we disable both ?

[flashjazzcat]

I believe disabling antic DMA is necessary to enable the CPU to keep up with the disk controller?

[Android8675]

Yeah, I heard the same thing somewhere, probably the only downside to the device is the need to blank the screen to access the drives. Stryker did release a version of the firmware (1.3g) that defaults to no color bars, but I don't have a way to flash the eprom. Since we're talking KMD has anyone sucessfully installed 2 floppy drives without having to solder the DS jumper for drive 1? I lost my flat floppy cable and was trying to just use a normal PC floppy drive cable with the twist, but drive 1 won't work.

[BillC]

Yeah, I heard the same thing somewhere, probably the only downside to the device is the need to blank the screen to access the drives. Stryker did release a version of the firmware (1.3g) that defaults to no color bars, but I don't have a way to flash the eprom. Since we're talking KMD has anyone sucessfully installed 2 floppy drives without having to solder the DS jumper for drive 1? I lost my flat floppy cable and was trying to just use a normal PC floppy drive cable with the twist, but drive 1 won't work.

Using the twisted cable one drive wouldn't receive a MOTOR signal. The Shugart standard had a single MOTOR(pin 16) and 4 drive select, while IBM reassigned DS0(pin 10) to become a second MOTOR signal and only used DS1(pin 12) and DS2(pin 14). They also use 2 drives both configured as DS1, the twist in the cable crosses the DS2 signal from the computer to the DS1 pin of the second drive with the MOTOR signals being crossed at the same time. If the controller doesn't have the second MOTOR signal on the pin 10 one drive won't work.

 

It should stil be possible to use an IBM twisted cable with 2 drives attached to devices designed to use a straight cable by connecting the DS0 pin to the MOTOR pin on the circuit board, configuring both drive as DS1, and configuring the device drives as 2&3(if it uses drives 1 to 4) or as 1&2(if it uses drive 0 to 3). I haven't tried this myself but I think it should work with the Karin Maxi drive, the ATR8000, and the Black Box floppy board. Atari used a trace between DS0 and MOTOR on the XF551 circuit board to function as drive select since it was designed as a single drive device.

[Android8675]

Using the twisted cable one drive wouldn't receive a MOTOR signal. The Shugart standard had a single MOTOR(pin 16) and 4 drive select, while IBM reassigned DS0(pin 10) to become a second MOTOR signal and only used DS1(pin 12) and DS2(pin 14). They also use 2 drives both configured as DS1, the twist in the cable crosses the DS2 signal from the computer to the DS1 pin of the second drive with the MOTOR signals being crossed at the same time. If the controller doesn't have the second MOTOR signal on the pin 10 one drive won't work.

 

It should stil be possible to use an IBM twisted cable with 2 drives attached to devices designed to use a straight cable by connecting the DS0 pin to the MOTOR pin on the circuit board, configuring both drive as DS1, and configuring the device drives as 2&3(if it uses drives 1 to 4) or as 1&2(if it uses drive 0 to 3). I haven't tried this myself but I think it should work with the Karin Maxi drive, the ATR8000, and the Black Box floppy board. Atari used a trace between DS0 and MOTOR on the XF551 circuit board to function as drive select since it was designed as a single drive device.

ok, so what it comes down too is you have to disconnect the ds0 jumper on the first drive (furthest from the KMD) no matter if you use a flat or PC twisted floppy cable.

 

I should just make a new cable and find some copper wick. Thanks much. -A.

[BillC]

ok, so what it comes down too is you have to disconnect the ds0 jumper on the first drive (furthest from the KMD) no matter if you use a flat or PC twisted floppy cable.

 

I should just make a new cable and find some copper wick. Thanks much. -A.

Since the twisted cable uses pin 10 for the MOTORB signal you can't use a drive configured as DS0 but since the drive has jumpers you can change it to DS1, and by connecting pin 10 to pin 16 on the KMD board it should be possible to use 2 DS1 configured drives as though they were configured as DS1/DS2 on a straight cable. The drive before the twist will respond as DS1, after the twist as DS2.

 

If you connect pins 10/16 on the KMD to use a twisted cable you would not be able to use DS0 with a straight cable either, but this would really only be an issue if you want to connect 4 drives.