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#include <OneWire.h>
/*
* DS2408 8-Channel Addressable Switch
*
* Writte by Glenn Trewitt, glenn at trewitt dot org
*
* Some notes about the DS2408:
* - Unlike most input/output ports, the DS2408 doesn't have mode bits to
* set whether the pins are input or output. If you issue a read command,
* they're inputs. If you write to them, they're outputs.
* - For reading from a switch, you should use 10K pull-up resisters.
*/
void PrintBytes(uint8_t* addr, uint8_t count, bool newline=0) {
for (uint8_t i = 0; i < count; i++) {
Serial.print(addr[i]>>4, HEX);
Serial.print(addr[i]&0x0f, HEX);
}
if (newline)
Serial.println();
}
void ReadAndReport(OneWire* net, uint8_t* addr) {
Serial.print(" Reading DS2408 ");
PrintBytes(addr, 8);
Serial.println();
uint8_t buf[13]; // Put everything in the buffer so we can compute CRC easily.
buf[0] = 0xF0; // Read PIO Registers
buf[1] = 0x88; // LSB address
buf[2] = 0x00; // MSB address
net->write_bytes(buf, 3);
net->read_bytes(buf+3, 10); // 3 cmd bytes, 6 data bytes, 2 0xFF, 2 CRC16
net->reset();
if (!OneWire::check_crc16(buf, 11, &buf[11])) {
Serial.print("CRC failure in DS2408 at ");
PrintBytes(addr, 8, true);
return;
}
Serial.print(" DS2408 data = ");
// First 3 bytes contain command, register address.
Serial.println(buf[3], BIN);
}
OneWire net(10); // on pin 10
void setup(void) {
Serial.begin(9600);
}
void loop(void) {
byte i;
byte present = 0;
byte addr[8];
if (!net.search(addr)) {
Serial.print("No more addresses.\n");
net.reset_search();
delay(1000);
return;
}
if (OneWire::crc8(addr, 7) != addr[7]) {
Serial.print("CRC is not valid!\n");
return;
}
if (addr[0] != 0x29) {
PrintBytes(addr, 8);
Serial.print(" is not a DS2408.\n");
return;
}
ReadAndReport(&net, addr);
}
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