prodos-drivers/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:

* [x] A ProDOS `.SYSTEM` file
* [x] Detects the presence of a Cricket
* [x] Installs a driver in memory following the ProDOS clock driver protocol
* [x] 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](https://github.com/cc65/cc65). The included `Makefile` is very specific to my machine - sorry about that.

[CRICKET.SYSTEM](cricket.system.s) is the result of the build.

## Notes

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

## Other Utilities

These `BRUN`able files are also built:
* [DATE](date.s) just prints the current ProDOS date/time, to verify the time is set and updating. It does not depend on having a Cricket.
* [TEST](test.s) attempts to identify an SSC in Slot 2 and the Cricket via the ID sequence, to test routines.
* [SET.DATE](set.date.s) sets the Cricket's current date.
* [SET.TIME](set.time.s) sets the Cricket's current time.

Also, an updated [NS.CLOCK.SYSTEM](ns.clock.system.s) is included that fixes a typo, removes beeps, and is less chatty so you can have both `NS.CLOCK.SYSTEM` and `CRICKET.SYSTEM` in the same hard disk image if you use the image across different hardware configurations.

## 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.