mirror of
https://github.com/tjboldt/Apple2-IO-RPi.git
synced 2024-11-25 21:33:15 +00:00
302 lines
6.3 KiB
Go
302 lines
6.3 KiB
Go
// Copyright Terence J. Boldt (c)2020-2021
|
|
// Use of this source code is governed by an MIT
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// This file is used for communicating with the Apple II data bus via the
|
|
// GPIO ports on the Raspberry Pi
|
|
package a2io
|
|
|
|
import (
|
|
"bytes"
|
|
"errors"
|
|
"fmt"
|
|
"time"
|
|
|
|
"periph.io/x/periph/conn/gpio"
|
|
"periph.io/x/periph/conn/gpio/gpioreg"
|
|
"periph.io/x/periph/host"
|
|
)
|
|
|
|
var edgeTimeout time.Duration
|
|
|
|
var out_write gpio.PinIO
|
|
var out_read gpio.PinIO
|
|
var out_reserved2 gpio.PinIO
|
|
var out_reserved1 gpio.PinIO
|
|
var out_bit7 gpio.PinIO
|
|
var out_bit6 gpio.PinIO
|
|
var out_bit5 gpio.PinIO
|
|
var out_bit4 gpio.PinIO
|
|
var out_bit3 gpio.PinIO
|
|
var out_bit2 gpio.PinIO
|
|
var out_bit1 gpio.PinIO
|
|
var out_bit0 gpio.PinIO
|
|
var in_write gpio.PinIO
|
|
var in_read gpio.PinIO
|
|
var in_reserved2 gpio.PinIO
|
|
var in_reserved1 gpio.PinIO
|
|
var in_bit7 gpio.PinIO
|
|
var in_bit6 gpio.PinIO
|
|
var in_bit5 gpio.PinIO
|
|
var in_bit4 gpio.PinIO
|
|
var in_bit3 gpio.PinIO
|
|
var in_bit2 gpio.PinIO
|
|
var in_bit1 gpio.PinIO
|
|
var in_bit0 gpio.PinIO
|
|
|
|
type A2Gpio struct {
|
|
}
|
|
|
|
func (a2 A2Gpio) Init() {
|
|
host.Init()
|
|
|
|
out_write = gpioreg.ByName("GPIO24")
|
|
out_read = gpioreg.ByName("GPIO25")
|
|
out_reserved2 = gpioreg.ByName("GPIO7") //note GPIO7 and CPIO8 require extra effort to use
|
|
out_reserved1 = gpioreg.ByName("GPIO8")
|
|
out_bit7 = gpioreg.ByName("GPIO5")
|
|
out_bit6 = gpioreg.ByName("GPIO11")
|
|
out_bit5 = gpioreg.ByName("GPIO9")
|
|
out_bit4 = gpioreg.ByName("GPIO10")
|
|
out_bit3 = gpioreg.ByName("GPIO22")
|
|
out_bit2 = gpioreg.ByName("GPIO27")
|
|
out_bit1 = gpioreg.ByName("GPIO17")
|
|
out_bit0 = gpioreg.ByName("GPIO4")
|
|
in_write = gpioreg.ByName("GPIO23")
|
|
in_read = gpioreg.ByName("GPIO18")
|
|
in_reserved2 = gpioreg.ByName("GPIO14")
|
|
in_reserved1 = gpioreg.ByName("GPIO15")
|
|
in_bit7 = gpioreg.ByName("GPIO12")
|
|
in_bit6 = gpioreg.ByName("GPIO16")
|
|
in_bit5 = gpioreg.ByName("GPIO20")
|
|
in_bit4 = gpioreg.ByName("GPIO21")
|
|
in_bit3 = gpioreg.ByName("GPIO26")
|
|
in_bit2 = gpioreg.ByName("GPIO19")
|
|
in_bit1 = gpioreg.ByName("GPIO13")
|
|
in_bit0 = gpioreg.ByName("GPIO6")
|
|
|
|
in_write.In(gpio.PullDown, gpio.BothEdges)
|
|
in_read.In(gpio.PullDown, gpio.BothEdges)
|
|
out_reserved1.Out(gpio.High)
|
|
out_reserved2.Out(gpio.High)
|
|
out_read.Out(gpio.High)
|
|
out_write.Out(gpio.High)
|
|
out_bit7.Out(gpio.Low)
|
|
out_bit6.Out(gpio.Low)
|
|
out_bit5.Out(gpio.Low)
|
|
out_bit4.Out(gpio.Low)
|
|
out_bit3.Out(gpio.Low)
|
|
out_bit2.Out(gpio.Low)
|
|
out_bit1.Out(gpio.Low)
|
|
out_bit0.Out(gpio.Low)
|
|
|
|
edgeTimeout = time.Second
|
|
}
|
|
|
|
func (a2 A2Gpio) ReadString() (string, error) {
|
|
var inBytes bytes.Buffer
|
|
for {
|
|
inByte, err := a2.ReadByte()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
if inByte == 0 {
|
|
break
|
|
}
|
|
inBytes.WriteByte(inByte)
|
|
}
|
|
return string(inBytes.Bytes()), nil
|
|
}
|
|
|
|
func (a2 A2Gpio) WriteString(outString string) error {
|
|
for _, character := range outString {
|
|
err := a2.WriteByte(byte(character) | 128)
|
|
if err != nil {
|
|
fmt.Printf("Failed to write string\n")
|
|
return err
|
|
}
|
|
}
|
|
a2.WriteByte(0)
|
|
return nil
|
|
}
|
|
|
|
func (a2 A2Gpio) ReadByte() (byte, error) {
|
|
// let the Apple II know we are ready to read
|
|
out_read.Out(gpio.Low)
|
|
|
|
// wait for the Apple II to write
|
|
for in_write.Read() == gpio.High {
|
|
if !in_write.WaitForEdge(edgeTimeout) {
|
|
out_read.Out(gpio.High)
|
|
return 0, errors.New("Timed out reading byte -- write stuck high\n")
|
|
}
|
|
}
|
|
|
|
// get a nibble of data
|
|
var data byte
|
|
data = 0
|
|
bit7 := in_bit7.Read()
|
|
bit6 := in_bit6.Read()
|
|
bit5 := in_bit5.Read()
|
|
bit4 := in_bit4.Read()
|
|
bit3 := in_bit3.Read()
|
|
bit2 := in_bit2.Read()
|
|
bit1 := in_bit1.Read()
|
|
bit0 := in_bit0.Read()
|
|
|
|
if bit7 == gpio.High {
|
|
data += 128
|
|
}
|
|
if bit6 == gpio.High {
|
|
data += 64
|
|
}
|
|
if bit5 == gpio.High {
|
|
data += 32
|
|
}
|
|
if bit4 == gpio.High {
|
|
data += 16
|
|
}
|
|
if bit3 == gpio.High {
|
|
data += 8
|
|
}
|
|
if bit2 == gpio.High {
|
|
data += 4
|
|
}
|
|
if bit1 == gpio.High {
|
|
data += 2
|
|
}
|
|
if bit0 == gpio.High {
|
|
data += 1
|
|
}
|
|
|
|
// let the Apple II know we are done reading
|
|
//fmt.Printf("let the Apple II know we are done reading\n")
|
|
out_read.Out(gpio.High)
|
|
|
|
// wait for the Apple II to finish writing
|
|
//fmt.Printf("wait for the Apple II to finish writing\n")
|
|
for in_write.Read() == gpio.Low {
|
|
if !in_write.WaitForEdge(edgeTimeout) {
|
|
return 0, errors.New("Timed out reading byte -- write stuck low")
|
|
}
|
|
}
|
|
|
|
return data, nil
|
|
}
|
|
|
|
func (a2 A2Gpio) WriteByte(data byte) error {
|
|
// check if the Apple II wants to send a byte to us first
|
|
if in_write.Read() == gpio.Low {
|
|
out_write.Out(gpio.High)
|
|
return errors.New("Can't write byte while byte is incoming")
|
|
}
|
|
|
|
// wait for the Apple II to be ready to read
|
|
for in_read.Read() == gpio.High {
|
|
if !in_read.WaitForEdge(edgeTimeout) {
|
|
out_write.Out(gpio.High)
|
|
return errors.New("Timed out writing byte -- read stuck high")
|
|
}
|
|
}
|
|
|
|
bit7 := gpio.Low
|
|
bit6 := gpio.Low
|
|
bit5 := gpio.Low
|
|
bit4 := gpio.Low
|
|
bit3 := gpio.Low
|
|
bit2 := gpio.Low
|
|
bit1 := gpio.Low
|
|
bit0 := gpio.Low
|
|
|
|
if ((data & 128) >> 7) == 1 {
|
|
bit7 = gpio.High
|
|
}
|
|
out_bit7.Out(bit7)
|
|
|
|
if ((data & 64) >> 6) == 1 {
|
|
bit6 = gpio.High
|
|
}
|
|
out_bit6.Out(bit6)
|
|
|
|
if ((data & 32) >> 5) == 1 {
|
|
bit5 = gpio.High
|
|
}
|
|
out_bit5.Out(bit5)
|
|
|
|
if ((data & 16) >> 4) == 1 {
|
|
bit4 = gpio.High
|
|
}
|
|
out_bit4.Out(bit4)
|
|
|
|
if ((data & 8) >> 3) == 1 {
|
|
bit3 = gpio.High
|
|
}
|
|
out_bit3.Out(bit3)
|
|
|
|
if ((data & 4) >> 2) == 1 {
|
|
bit2 = gpio.High
|
|
}
|
|
out_bit2.Out(bit2)
|
|
|
|
if ((data & 2) >> 1) == 1 {
|
|
bit1 = gpio.High
|
|
}
|
|
out_bit1.Out(bit1)
|
|
|
|
if (data & 1) == 1 {
|
|
bit0 = gpio.High
|
|
}
|
|
out_bit0.Out(bit0)
|
|
|
|
// let Apple II know we're writing
|
|
out_write.Out(gpio.Low)
|
|
|
|
// wait for the Apple II to finsih reading
|
|
//fmt.Printf("wait for the Apple II to finsih reading\n")
|
|
for in_read.Read() == gpio.Low {
|
|
if !in_read.WaitForEdge(edgeTimeout) {
|
|
out_write.Out(gpio.High)
|
|
return errors.New("Timed out writing byte -- read stuck low")
|
|
}
|
|
}
|
|
|
|
// let the Apple II know we are done writing
|
|
out_write.Out(gpio.High)
|
|
return nil
|
|
}
|
|
|
|
func (a2 A2Gpio) WriteBlock(buffer []byte) error {
|
|
for i := 0; i < 512; i++ {
|
|
err := a2.WriteByte(buffer[i])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (a2 A2Gpio) ReadBlock(buffer []byte) error {
|
|
var err error
|
|
for i := 0; i < 512; i++ {
|
|
buffer[i], err = a2.ReadByte()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (a2 A2Gpio) WriteBuffer(buffer []byte) error {
|
|
bufferSize := len(buffer)
|
|
for i := 0; i < bufferSize; i++ {
|
|
err := a2.WriteByte(buffer[i])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|