Balboa32U4LCD.h

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// Copyright Pololu Corporation.  For more information, see http://www.pololu.com/

#pragma once

#include <PololuHD44780.h>
#include <FastGPIO.h>
#include <USBPause.h>

class Balboa32U4LCD : public PololuHD44780Base
{
    // Pin assignments
    static const uint8_t rs = 4, e = 11, db4 = 14, db5 = 17, db6 = 13, db7 = IO_D5;

public:

    virtual void initPins()
    {
        FastGPIO::Pin<e>::setOutputLow();
    }

    virtual void send(uint8_t data, bool rsValue, bool only4bits)
    {
        // Temporarily disable USB interrupts because they write some pins
        // we are using as LCD pins.
        USBPause usbPause;

        // Save the state of the RS and data pins.  The state automatically
        // gets restored before this function returns.
        FastGPIO::PinLoan<rs> loanRS;
        FastGPIO::PinLoan<db4> loanDB4;
        FastGPIO::PinLoan<db5> loanDB5;
        FastGPIO::PinLoan<db6> loanDB6;
        FastGPIO::PinLoan<db7> loanDB7;

        // Drive the RS pin high or low.
        FastGPIO::Pin<rs>::setOutput(rsValue);

        // Send the data.
        if (!only4bits) { sendNibble(data >> 4); }
        sendNibble(data & 0x0F);
    }

private:

    void sendNibble(uint8_t data)
    {
        FastGPIO::Pin<db4>::setOutput(data >> 0 & 1);
        FastGPIO::Pin<db5>::setOutput(data >> 1 & 1);
        FastGPIO::Pin<db6>::setOutput(data >> 2 & 1);
        FastGPIO::Pin<db7>::setOutput(data >> 3 & 1);

        FastGPIO::Pin<e>::setOutputHigh();
        _delay_us(1);   // Must be at least 450 ns.
        FastGPIO::Pin<e>::setOutputLow();
        _delay_us(1);   // Must be at least 550 ns.
    }
};