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Ivan Izaguirre
d67b946a09
The Apple II Parallel Printer Interface card shows whether the printer is ready in the byte at $CnC1 of its ROM: the acknowledge of the printer drives the address line A6 of the PROM, and $CnC1 reads $90, a BCC on itself, while the printer is busy, and $10, a BPL, once it is ready. The ROM here had $90, busy forever. Its own firmware still printed, since BCC and BPL both branch there, but programs with drivers of their own that poll bit 7 of $CnC1, as The Print Shop, waited before the first line. The file is always ready, so the ROM now has $10 at $C1.
74 lines
2.2 KiB
Go
74 lines
2.2 KiB
Go
package izapple2
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import (
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"os"
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)
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/*
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Apple II Parallel Printer Interface card.
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See:
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https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Parallel/Apple%20II%20Parallel%20Printer%20Interface%20Card/
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The card tells whether the printer is ready by the byte at $CnC1 of its ROM:
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the acknowledge of the printer drives the address line A6 of the PROM, so
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that while the printer is busy $CnC1 reads $90, a BCC on itself where the
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firmware waits, and once it is ready $10, a BPL out of the loop. Programs
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with drivers of their own, as The Print Shop, poll bit 7 of $CnC1. A file is
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always ready, so the ROM has $10 there.
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*/
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// CardParallelPrinter represents a Parallel Printer Interface card
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type CardParallelPrinter struct {
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cardBase
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file *os.File
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ascii bool
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}
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func newCardParallelPrinterBuilder() *cardBuilder {
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return &cardBuilder{
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name: "Parallel Printer Interface",
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description: "Card to dump to a file what would be printed to a parallel printer",
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defaultParams: &[]paramSpec{
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{"file", "File to store the printed code", "printer.out"},
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{"ascii", "Remove the 7 bit. Useful for normal text printing, but breaks graphics printing ", "false"},
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},
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buildFunc: func(params map[string]string) (Card, error) {
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var c CardParallelPrinter
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c.ascii = paramsGetBool(params, "ascii")
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filepath := paramsGetPath(params, "file")
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f, err := os.OpenFile(filepath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
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if err != nil {
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return nil, err
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}
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c.file = f
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err = c.loadRomFromResource("<internal>/Apple II Parallel Printer Interface Card ROM fixed.bin", cardRomSimple)
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if err != nil {
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return nil, err
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}
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return &c, nil
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},
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}
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}
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func (c *CardParallelPrinter) assign(a *Apple2, slot int) {
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c.addCardSoftSwitchW(0, func(value uint8) {
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c.printByte(value)
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}, "PARALLELDEVW")
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c.addCardSoftSwitchR(4, func() uint8 {
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return 0xff // TODO: What are the bit values?
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}, "PARALLELSTATUSR")
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c.cardBase.assign(a, slot)
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}
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func (c *CardParallelPrinter) printByte(value uint8) {
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if c.ascii {
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// As text the MSB has to be removed, but if done, graphics modes won't work
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value &= 0x7f // Remove the MSB bit
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}
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c.file.Write([]byte{value})
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}
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