[Coco] Speech and Sound Cartridge under NitrOS9

Barry Nelson barry.nelson at amobiledevice.com
Wed Dec 30 23:58:30 EST 2015

Quite some time ago, I modified the speech/sound cartridge driver to switch to .89Mhz while accessing the speech cartridge and switch back when returning to the OS. I have been using this driver for many years with my unmodified speech/sound cartridge with both level II OS9 and NitrOS9 level II. Unfortunately I can not locate the source code, but it is essentially the stock sscpak driver with instructions added to drop to slow speed when entering the write routine, and return to 2Mhz when exiting. I posted it here


This file contains the device descriptor and the device driver. Copy the file to an OS9 or NitrOS9 level 2 disk, set the "e" attribute, and load the file.

Header for : SSC
Module size: $3D  #61
Module CRC : $AFF6FA (Good)
Hdr parity : $D5
File Mgr   : SCF
Driver     : SSCPAK
Edition    : $53  #83
Ty/La At/Rv: $F1 $82
Device Descriptor mod, 6809 Obj, re-ent, R/O

Header for : SSCPAK
Module size: $D9  #217
Module CRC : $2E1B85 (Good)
Hdr parity : $01
Exec. off  : $0015  #21
Data size  : $001E  #30
Edition    : $01  #1
Ty/La At/Rv: $E1 $82
Device Driver mod, 6809 Obj, re-ent, R/O

> K. Pruitt pruittk at roadrunner.com 
> Wed Dec 30 11:34:47 EST 2015
> Is it at all possible to operate an UNMODIFIED speech and sound cartridge
> under NitrOS9 Level 2?
> Here's what I am doing... I am halting the interrupts and dropping the CoCo 
> down to 0.89Mhz. This allows the Speech and Sound cartridge to speak under 
> Level 2.
> I'm happy to post the code I am using, but it's just the BASIC listing 
> starting on page 5 of the device's manual translated in to assembly.
> This works fine under stock Level 2 OS-9 but leaves the system unstable. It 
> works on NitrOS9 fine as far as speaking goes, but it never gets to the 
> point of turning the interrupts back on and returning the CoCo to 1.79Mhz. A 
> reset is required to recover from the hang-up as the interrupts are off
> .
> By the way, I use this method of turning off the interrupts and dropping the 
> CoCo down to 0.89Mhz quite successfully with the Plug 'n Power controller. 
> I've been running it for a couple of years now under NitrOS9 and is hasn't 
> failed me once or caused any issues with the OS.
> I installed the speech and sound cartridge drivers to play around with them 
> (I assume they are for the modified cartridge) but when they are installed 
> NitrOS9 won't boot for me. If I just load the drivers I get an error 207 
> when I try and send something to them. This takes place no matter if the 
> Speech and Sound cartridge is plugged in or not.
> I'm just screwing around with the sound and speech cartridge here and am 
> just curious if what I an trying is even possible to pull off. If anybody 
> would care to chime in on the speech and sound cartridge I would really 
> appreciate the input.
> Thanks

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