56 lines
2.6 KiB
Markdown
56 lines
2.6 KiB
Markdown
# _The Cricket!_ — ProDOS Clock Driver
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I acquired a Cricket sound/clock peripheral on eBay. Therefore it is now critical that we have a conforming ProDOS clock driver for it.
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> STATUS: Works on my machine!
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## Background
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_"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.
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The disks supplied with the device include:
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* `/CRICKET/PRODOS.MOD` which can be BRUN to patch ProDOS in memory with a clock driver.
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* A modified version of ProDOS
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* A utility to patch ProDOS on disk
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## `CRICKET.SYSTEM`
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Like the `NS.CLOCK.SYSTEM` (by "CAP"), `CRICKET.SYSTEM` has these features:
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* [x] A ProDOS `.SYSTEM` file
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* [x] Detects the presence of a Cricket
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* [x] Installs a driver in memory following the ProDOS clock driver protocol
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* [x] Chains to the next `.SYSTEM` file (e.g. `BASIC.SYSTEM`)
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Successfully tested on real hardware. (Laser 128EX, an Apple //c clone — including at 3x speed!)
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## Build
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Requires [cc65](https://github.com/cc65/cc65). The included `Makefile` is very specific to my machine - sorry about that.
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[CRICKET.SYSTEM](cricket.system.s) is the result of the build.
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## Notes
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I ended up disassembling both [NS.CLOCK.SYSTEM](../ns.clock/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.
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## Other Utilities
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These `BRUN`able files are also built:
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* [TEST](test.s) attempts to identify an SSC in Slot 2 and the Cricket via the ID sequence, to test routines.
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* [SET.DATE](set.date.s) sets the Cricket's current date.
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* [SET.TIME](set.time.s) sets the Cricket's current time.
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## Resources
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Cricket disks on Asimov:
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* ftp://ftp.apple.asimov.net/pub/apple_II/images/hardware/sound/cricket_disk1.po
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* ftp://ftp.apple.asimov.net/pub/apple_II/images/hardware/sound/cricket_disk2.po
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Cricket Manual on Asimov:
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* ftp://ftp.apple.asimov.net/pub/apple_II/documentation/hardware/sound/Street%20Electronics%20The%20Cricket.pdf
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## FYI...
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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.
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