ModbusASCII.h

#ifndef __ModbusPotato_ModbusASCII_h__
#define __ModbusPotato_ModbusASCII_h__
#include "ModbusInterface.h"
namespace ModbusPotato
{
    /// <summary>
    /// This class handles the RTU based protocol for Modbus.
    /// </summary>
    /// <remarks>
    /// See the IFramer interface for a complete description of the public
    /// methods.
    ///
    /// The setup() method must be called with the correct baud rate before
    /// using this class in order to calculate the proper inter-character and
    /// inter-frame delays.
    /// </remarks>
    class CModbusASCII : public IFramer
    {
    public:
        /// <summary>
        /// Constructor for the RTU framer.
        /// </summary>
        CModbusASCII(IStream* stream, ITimeProvider* timer, uint8_t* buffer, size_t buffer_max);

        /// <summary>
        /// Sets the timeout, in milliseconds
        /// </summary>
        /// <remarks>
        /// The poll() method must be called and the timer adjusted according
        /// to the semantics described in IFramer::poll() for the new timeout
        /// to take effect.
        /// </remarks>
        void set_timeout(unsigned int milliseconds);

        unsigned long poll();
        bool begin_send();
        void send();
        void finished();
        bool frame_ready() const override { return m_state == state_frame_ready; }
    private:
        enum
        {
            LRC_LEN = 1,
            min_pdu_length = 2, // minimum PDU length, excluding the station address. function code and one LRC byte
            default_timeout = 1000, // default timeout, in milliseconds
        };
        uint8_t m_checksum;
        uint8_t m_buffer_tx_pos;
        enum state_type
        {
            state_exception,
            state_idle,
            state_frame_ready,
            state_queue,
            state_collision,
            state_rx_addr_high,
            state_rx_addr_low,
            state_rx_pdu_high,
            state_rx_pdu_low,
            state_rx_cr,
            state_tx_sof,
            state_tx_addr_high,
            state_tx_addr_low,
            state_tx_pdu_high,
            state_tx_pdu_low,
            state_tx_lrc_high,
            state_tx_lrc_low,
            state_tx_cr,
            state_tx_lf,
            state_tx_wait,
        };
        state_type m_state;
        system_tick_t m_last_ticks;
        system_tick_t m_T1s;
    };
}
#endif