prodos-drivers/clocks/cricket/README.md

The Cricket! — ProDOS Clock Driver

I acquired a Cricket sound/clock peripheral on eBay. Therefore it is now critical that we have a conforming ProDOS clock driver for it.

STATUS: Works on my machine!

Background

"The Cricket!" by Street Electronics Corporation, released in 1984, is a hardware peripheral for the Apple //c computer. It plugs into the serial port and offers a multi-voice sound synthesizer, a speech synthesizer, and a real-time clock.

The disks supplied with the device include:

• /CRICKET/PRODOS.MOD which can be BRUN to patch ProDOS in memory with a clock driver.
• A modified version of ProDOS
• A utility to patch ProDOS on disk

CRICKET.SYSTEM

Like the NS.CLOCK.SYSTEM (by "CAP"), CRICKET.SYSTEM has these features:

• A ProDOS .SYSTEM file
• Detects the presence of a Cricket
• Installs a driver in memory following the ProDOS clock driver protocol
• Chains to the next .SYSTEM file (e.g. BASIC.SYSTEM)

Successfully tested on real hardware. (Laser 128EX, an Apple //c clone — including at 3x speed!)

Build

Requires cc65. The included Makefile is very specific to my machine - sorry about that.

CRICKET.SYSTEM is the result of the build.

Notes

I ended up disassembling both NS.CLOCK.SYSTEM (to understand the SYSTEM chaining - what a pain!) and The Cricket!'s PRODOS.MOD and melding them together, adding in the detection routine following the protocol in the manual.

Other Utilities

These BRUNable files are also built:

• TEST attempts to identify an SSC in Slot 2 and the Cricket via the ID sequence, to test routines.
• SET.DATE sets the Cricket's current date.
• SET.TIME sets the Cricket's current time.

Resources

Cricket disks on Asimov:

• ftp://ftp.apple.asimov.net/pub/apple_II/images/hardware/sound/cricket_disk1.po
• ftp://ftp.apple.asimov.net/pub/apple_II/images/hardware/sound/cricket_disk2.po

Cricket Manual on Asimov:

• ftp://ftp.apple.asimov.net/pub/apple_II/documentation/hardware/sound/Street%20Electronics%20The%20Cricket.pdf

FYI...

In the Cricket manual there is a short sample BASIC program to set the clock without the use of any assembly routines, using PR#2 to talk to the serial card followed by PRINT statements. This does not appear to work from ProDOS with the clock driver in place - the time ends up temporarily scrambled until the clock sorts itself out again. Assembly language routines do work, however. I believe ProDOS attempts to read the clock during the execution of the basic program, which interferes the device.