ElectricImpSampleCode/1-wire.multiple.device.nut

## 1-wire.multiple.device.nut
// FUNCTIONS
function onewireReset() {
    // Configure UART for 1-Wire RESET timing
    ow.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS);
    ow.write(0xF0);
    ow.flush();
    local read = ow.read();
    if (read == -1) {
        // No UART data at all
        server.log("No circuit connected to UART.");
        return false;
    } else if (read == 0xF0) {
        // UART RX will read TX if there's no device connected
        server.log("No 1-Wire devices are present.");
        return false;
    } else {
        // Switch UART to 1-Wire data speed timing
        ow.configure(115200, 8, PARITY_NONE, 1, NO_CTSRTS);
        return true;
    }
}

function onewireWriteByte(byte) {
    for (local i = 0 ; i < 8 ; i++) {
        // Run through the bits in the byte, extracting the
        // LSB (bit 0) and sending it to the bus
        byte = byte >> 1;
        onewireBit(byte & 0x01);
    }
}

function onewireReadByte() {
    local byte = 0;
    for (local i = 0 ; i < 8 ; i++) {
        // Build up byte bit by bit, LSB first
        byte = (byte >> 1) + 0x80 * onewireBit(1);
    }
    return byte;
}

function onewireBit(bit) {
    bit = bit ? 0xFF : 0x00;
    ow.write(bit);
    ow.flush();
    local returnVal = ow.read() == 0xFF ? 1 : 0;
    return returnVal;
}

function onewireSearch(nextNode) {
    // 'lastForkPoint' records where the device tree last branched
    local lastForkPoint = 0;

    // Reset the bus and exit if no device found
    if (onewireReset()) {
        // There are 1-Wire device(s) on the bus, so issue the 1-Wire SEARCH command (0xF0)
        onewireWriteByte(0xF0);

        // Work along the 64-bit ROM code, bit by bit, from LSB to MSB
        for (local i = 64 ; i > 0 ; i--) {
            local byte = (i - 1) / 8;

            // Read bit from bus
            local bit = onewireBit(1);

            // Read the next bit
            if (onewireBit(1)) {
                if (bit) {
                    // Both bits are 1 which indicates that there are no further devices
                    // on the bus, so put pointer back to the start and break out of the loop
                    lastForkPoint = 0;
                    break;
                }
            } else if (!bit) {
                // First and second bits are both 0: we're at a node
                if (nextNode > i || (nextNode != i && (id[byte] & 1))) {
                    // Take the '1' direction on this point
                    bit = 1;
                    lastForkPoint = i;
                }
            }

            // Write the 'direction' bit. For example, if it's 1 then all further
            // devices with a 0 at the current ID bit location will go offline
            onewireBit(bit);

            // Write the bit to the current ID record
            id[byte] = (id[byte] >> 1) + 0x80 * bit;
        }
    }

    // Return the last fork point so it can form the start of the next search
    return lastForkPoint
}

function onewireDevices() {
    id <- [0,0,0,0,0,0,0,0];
    nextDevice <- 65;

    while (nextDevice) {
        nextDevice = onewireSearch(nextDevice);

        // Store the device ID discovered by one_wire_search() in an array
        // Nb. We need to clone the array, id, so that we correctly save
        // each one rather than the address of a single array
        peripherals.push(clone(id));
    }
}

function getTemp() {
    local tempLSB = 0;
    local tempMSB = 0;
    local tempCelsius = 0;

    // Wake up in five seconds for the next reading
    imp.wakeup(5.0, getTemp);

    // Reset the 1-Wire bus
    local result = onewireReset();

    if (result) {
        // Issue 1-Wire Skip ROM command (0xCC) to select all devices on the bus
        onewireWriteByte(0xCC);

        // Issue DS18B20 Convert command (0x44) to tell all DS18B20s to get the temperature
        // Even if other devices don't ignore this, we will not read them
        onewireWriteByte(0x44);

        // Wait 750ms for the temperature conversion to finish
        imp.sleep(0.75);

        foreach (device, peripheralId in peripherals) {
            // Run through the list of discovered peripheral devices, getting the temperature
            // if a given device is of the correct family number: 0x28 for BS18B20
            if (peripheralId[7] == 0x28) {
                onewireReset();

                // Issue 1-Wire MATCH ROM command (0x55) to select device by ID
                onewireWriteByte(0x55);

                // Write out the 64-bit ID from the array's eight bytes
                for (local i = 7 ; i >= 0 ; i--) {
                    onewireWriteByte(peripheralId[i]);
                }

                // Issue the DS18B20's READ SCRATCHPAD command (0xBE) to get temperature
                onewireWriteByte(0xBE);

                // Read the temperature value from the sensor's RAM
                tempLSB = onewireReadByte();
                tempMSB = onewireReadByte();

                // Signal that we don't need any more data by resetting the bus
                onewireReset();

                // Calculate the temperature from LSB and MSB, making sure we
                // sign-extend the signed 16-bit temperature readinf ('raw')
                // to a Squirrel 32-bit signed integer ('tempCelsius')
                local raw = (tempMSB << 8) + tempLSB;
                tempCelsius = ((raw << 16) >> 16) * 0.0625;
                server.log(format("Device: %02d Family: %02x Serial: %02x%02x%02x%02x%02x%02x Temp: %3.2f", (device + 1), peripheralId[7], peripheralId[1], peripheralId[2], peripheralId[3], peripheralId[4], peripheralId[5], peripheralId[6], tempCelsius));
            }
        }
    }
}

// RUNTIME START
// Set up the 1-Wire UART. This is for an imp001 -
// change the UART object in the line below for other imps
ow <- hardware.uart12;
peripherals <- [];

// Enumerate the devices on the bus
onewireDevices();

// Start sampling temperature data
getTemp();

## 1-wire.single.device.nut
// FUNCTIONS
function onewireReset() {
    // Configure UART for 1-Wire RESET timing
    ow.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS);
    ow.write(0xF0);
    ow.flush();
    local read = ow.read();
    if (read == -1) {
        // No UART data at all
        server.log("No circuit connected to UART.");
        return false;
    } else if (read == 0xF0) {
        // UART RX will read TX if there's no device connected
        server.log("No 1-Wire devices are present.");
        return false;
    } else {
        // Switch UART to 1-Wire data speed timing
        ow.configure(115200, 8, PARITY_NONE, 1, NO_CTSRTS);
        return true;
    }
}

function onewireWriteByte(byte) {
    for (local i = 0 ; i < 8 ; ++i) {
        // Run through the bits in the byte, extracting the
        // LSB (bit 0) and sending it to the bus
        byte = byte >> 1;
        onewireBit(byte & 0x01);
    }
}

function onewireReadByte() {
    local byte = 0;
    for (local i = 0 ; i < 8 ; ++i) {
        // Build up byte bit by bit, LSB first
        byte = (byte >> 1) + 0x80 * onewireBit(1);
    }
    return byte;
}

function onewireBit(bit) {
    bit = bit ? 0xFF : 0x00;
    ow.write(bit);
    ow.flush();
    local returnValue = ow.read() == 0xFF ? 1 : 0;
    return returnValue;
}

function awakeAndGetTemp() {
    // Wake up every 30 seconds and write to the server
    local tempLSB = 0;
    local tempMSB = 0;
    local tempCelsius = 0;

    // Run loop again in 30 seconds
    imp.wakeup(30.0, awakeAndGetTemp);

    if (onewireReset()) {
        onewireWriteByte(0xCC);  // 1-Wire Skip ROM command
        onewireWriteByte(0x44);

        // Wait for at least 750ms for data to be collated
        imp.sleep(0.8);

        // Get the data
        onewireReset();
        onewireWriteByte(0xCC);  // 1-Wire Skip ROM command
        onewireWriteByte(0xBE);  // Tell sensor to take a reading

        tempLSB = onewireReadByte();
        tempMSB = onewireReadByte();

        // Reset bus to stop sensor sending unwanted data
        onewireReset();

        // Calculate the temperature from LSB and MSB, making sure we
        // sign-extend the signed 16-bit temperature readinf ('raw')
        // to a Squirrel 32-bit signed integer ('tempCelsius')
        local raw = (tempMSB << 8) + tempLSB;
        tempCelsius = ((raw << 16) >> 16) * 0.0625;
        server.log(format("Temperature: %3.2f degrees C", tempCelsius));
    }
}

// RUNTIME START
// Set up the 1-Wire UART. This is for an imp001 -
// change the UART object in the line below for other imps
ow <- hardware.uart12;
awakeAndGetTemp();
	// FUNCTIONS
	function onewireReset() {
	// Configure UART for 1-Wire RESET timing
	ow.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS);
	ow.write(0xF0);
	ow.flush();
	local read = ow.read();
	if (read == -1) {
	// No UART data at all
	server.log("No circuit connected to UART.");
	return false;
	} else if (read == 0xF0) {
	// UART RX will read TX if there's no device connected
	server.log("No 1-Wire devices are present.");
	return false;
	} else {
	// Switch UART to 1-Wire data speed timing
	ow.configure(115200, 8, PARITY_NONE, 1, NO_CTSRTS);
	return true;
	}
	}

	function onewireWriteByte(byte) {
	for (local i = 0 ; i < 8 ; i++) {
	// Run through the bits in the byte, extracting the
	// LSB (bit 0) and sending it to the bus
	byte = byte >> 1;
	onewireBit(byte & 0x01);
	}
	}

	function onewireReadByte() {
	local byte = 0;
	for (local i = 0 ; i < 8 ; i++) {
	// Build up byte bit by bit, LSB first
	byte = (byte >> 1) + 0x80 * onewireBit(1);
	}
	return byte;
	}

	function onewireBit(bit) {
	bit = bit ? 0xFF : 0x00;
	ow.write(bit);
	ow.flush();
	local returnVal = ow.read() == 0xFF ? 1 : 0;
	return returnVal;
	}

	function onewireSearch(nextNode) {
	// 'lastForkPoint' records where the device tree last branched
	local lastForkPoint = 0;

	// Reset the bus and exit if no device found
	if (onewireReset()) {
	// There are 1-Wire device(s) on the bus, so issue the 1-Wire SEARCH command (0xF0)
	onewireWriteByte(0xF0);

	// Work along the 64-bit ROM code, bit by bit, from LSB to MSB
	for (local i = 64 ; i > 0 ; i--) {
	local byte = (i - 1) / 8;

	// Read bit from bus
	local bit = onewireBit(1);

	// Read the next bit
	if (onewireBit(1)) {
	if (bit) {
	// Both bits are 1 which indicates that there are no further devices
	// on the bus, so put pointer back to the start and break out of the loop
	lastForkPoint = 0;
	break;
	}
	} else if (!bit) {
	// First and second bits are both 0: we're at a node
	if (nextNode > i \|\| (nextNode != i && (id[byte] & 1))) {
	// Take the '1' direction on this point
	bit = 1;
	lastForkPoint = i;
	}
	}

	// Write the 'direction' bit. For example, if it's 1 then all further
	// devices with a 0 at the current ID bit location will go offline
	onewireBit(bit);

	// Write the bit to the current ID record
	id[byte] = (id[byte] >> 1) + 0x80 * bit;
	}
	}

	// Return the last fork point so it can form the start of the next search
	return lastForkPoint
	}

	function onewireDevices() {
	id <- [0,0,0,0,0,0,0,0];
	nextDevice <- 65;

	while (nextDevice) {
	nextDevice = onewireSearch(nextDevice);

	// Store the device ID discovered by one_wire_search() in an array
	// Nb. We need to clone the array, id, so that we correctly save
	// each one rather than the address of a single array
	peripherals.push(clone(id));
	}
	}

	function getTemp() {
	local tempLSB = 0;
	local tempMSB = 0;
	local tempCelsius = 0;

	// Wake up in five seconds for the next reading
	imp.wakeup(5.0, getTemp);

	// Reset the 1-Wire bus
	local result = onewireReset();

	if (result) {
	// Issue 1-Wire Skip ROM command (0xCC) to select all devices on the bus
	onewireWriteByte(0xCC);

	// Issue DS18B20 Convert command (0x44) to tell all DS18B20s to get the temperature
	// Even if other devices don't ignore this, we will not read them
	onewireWriteByte(0x44);

	// Wait 750ms for the temperature conversion to finish
	imp.sleep(0.75);

	foreach (device, peripheralId in peripherals) {
	// Run through the list of discovered peripheral devices, getting the temperature
	// if a given device is of the correct family number: 0x28 for BS18B20
	if (peripheralId[7] == 0x28) {
	onewireReset();

	// Issue 1-Wire MATCH ROM command (0x55) to select device by ID
	onewireWriteByte(0x55);

	// Write out the 64-bit ID from the array's eight bytes
	for (local i = 7 ; i >= 0 ; i--) {
	onewireWriteByte(peripheralId[i]);
	}

	// Issue the DS18B20's READ SCRATCHPAD command (0xBE) to get temperature
	onewireWriteByte(0xBE);

	// Read the temperature value from the sensor's RAM
	tempLSB = onewireReadByte();
	tempMSB = onewireReadByte();

	// Signal that we don't need any more data by resetting the bus
	onewireReset();

	// Calculate the temperature from LSB and MSB, making sure we
	// sign-extend the signed 16-bit temperature readinf ('raw')
	// to a Squirrel 32-bit signed integer ('tempCelsius')
	local raw = (tempMSB << 8) + tempLSB;
	tempCelsius = ((raw << 16) >> 16) * 0.0625;
	server.log(format("Device: %02d Family: %02x Serial: %02x%02x%02x%02x%02x%02x Temp: %3.2f", (device + 1), peripheralId[7], peripheralId[1], peripheralId[2], peripheralId[3], peripheralId[4], peripheralId[5], peripheralId[6], tempCelsius));
	}
	}
	}
	}

	// RUNTIME START
	// Set up the 1-Wire UART. This is for an imp001 -
	// change the UART object in the line below for other imps
	ow <- hardware.uart12;
	peripherals <- [];

	// Enumerate the devices on the bus
	onewireDevices();

	// Start sampling temperature data
	getTemp();