/***************************************************************************
 * This code and information is provided "as is" without warranty of any   *
 * kind, either expressed or implied, including but not limited to the     *
 * implied warranties of merchantability and/or fitness for a particular   *
 * purpose.                                                                *
 *                                                                         *
 * Copyright (C) 2006 Teridian Semiconductor Corp. All Rights Reserved.    *
 ***************************************************************************/
//**************************************************************************
//  DESCRIPTION: 71M651x POWER METER - IO Routines.
// 
//  AUTHOR:  RGV
//
//  HISTORY: See end of file
//**************************************************************************
// File: IO_LITE.C
//               
// IO subroutines for use by the calibration loader.
//
#include "options.h"
// if the CLI's superior serial logic is available, use it.
#if CAL_LDR && !CLI
#include <ctype.h>
#include "irq.h"
#include "batmodes.h"
#include "main.h"
#include "defaults.h"
#include "meter.h"
#include "io.h"  //check definitions against the actual code
#define XON 0x11
#define XOFF 0x13

/* the choice of the hardware abstraction layer (HAL)
 * adapts this code to either serial port */
#if SERIAL0
#include "ser0.h" /* include the HAL for UART 0 */
#elif SERIAL1
#include "ser1.h" /* include the HAL for UART 1 */
#else
#error no known serial port selected
#endif
#include "io.h"   // test routines here against the interface

uint8_t mpu_div = -1;
uint8_t my_batmode = 0;
bool xmit_rdy;
bool xoff_sent;
#define sbuf 32  // must be a power of two
#define mbuf (sbuf - 1)
uint8_t achRx[sbuf];
uint8d_t ichRxIn, ichRxOut, cchRx;

// lightweight timerless timeout using accumulation intervals
uint32_t my_cai;
bool io_timeout;  // the flag read by high level protocols

#pragma save
#pragma NOAREGS
// initialize the serial port, if it's needed
static void init (void) small reentrant
{
   if (mpu_div != (CONFIG0 & MPU_DIV) || my_batmode != batmode_is_brownout())
   {
       uint8_t baud;
       irq_disable();
       #if SERIAL0
       baud = defaults[BAUD0_IDX];
       #elif SERIAL1
       baud = defaults[BAUD1_IDX];
       #else
       #error unknown serial port
       #endif
       #if M6520
       if (BATTERY_MODE_ENABLE)
           baud = _RATE_300;
       #endif
       ser_initialize(baud);
       mpu_div = CONFIG0 & MPU_DIV;
       my_batmode = batmode_is_brownout();
       ichRxIn = ichRxOut = cchRx = 0;
       xmit_rdy = 0;
       xoff_sent = 1;
       ser_enable_rcv_rdy(); // enable the receiver interrupt
       irq_enable();
       my_cai = cai;
       io_timeout = 0;
   }
}
#pragma restore

// very basic polling output; uses the above serial driver
#pragma save
#pragma NOAREGS
void putc (uint8_t ch) small reentrant
{
   init();
   // the low level driver is designed so that one can poll
   // the TI bit to determine that the transmit buffer is ready
   // for another character.  Alas, enabling the interrupt
   // causes this bit to be reset in the interrupt routine.
   while (!xmit_rdy)
   {
       main_background ();
       init();
   }
   xmit_rdy = 0;
   ser_xmit(ch);
}
#pragma restore

bool cmd_pending (void)
{
    if (cchRx <= 0)
    {
        init();
        return 0;
    }
    else
        return 1;
}

// very basic interrupting input; uses the above serial driver
#pragma save
#pragma NOAREGS
uint8_t getc (void) small reentrant
{
    uint8_t ch;
    init ();
    if (io_timeout)
        return 0;
    else
    {
        my_cai = cai;
        while (!cmd_pending())
        {
            main_background (); // runs everything except serial IO
            init ();
            if (xoff_sent)
            {
                putc(XON);
                xoff_sent = 0;
            }
            // little timer that counts accumulation intervals
            // This saves the code space of stm.c
            if ((cai - my_cai) > 30)
            {
                io_timeout = 1;
                return 0;
            }
        } 
        ichRxOut &= mbuf;
        ch = achRx[ ichRxOut++ ];
        irq_disable();
        --cchRx;
        irq_enable();
        return ch;
    }
}
#pragma restore

#pragma save
#pragma NOAREGS
void cli_in (void) small reentrant
{
    static uint8_t data rx;

    rx = ser_rcv();

    // XON/XOFF is handled by sending XON when the calibration loader
    // is waiting for a message, and sending XOFF after the message's
    // checksum is received.  This is just a buffering arrangement
    // so the PC's driveling isn't lost
    if (XON != rx && XOFF != rx && cchRx < sbuf)
    {
        ichRxIn &= mbuf;
        achRx[ ichRxIn++ ] = rx;
        irq_disable();
        ++cchRx;
        irq_enable();
        if (cchRx > (sbuf/4) && xmit_rdy && !xoff_sent)
        {
            xmit_rdy = 0;
            ser_xmit(XOFF);
            xoff_sent = 1;
        }
    }
}
#pragma restore

#pragma save
#pragma NOAREGS
// the low level driver is designed so that one can poll
// the TI bit to determine that the transmit buffer is ready
// for another character.  Alas, enabling the interrupt
// causes an interrupt when TI is set, because there is no
// separate enable bit for the transmit interrupt.
void cli_out (void) small reentrant
{
    xmit_rdy = 1;
    ser_disable_xmit_rdy();
}
#pragma restore

// Send single ASCII hex or decimal digit to DTE.
static void send_digit (uint8_t c)
{
    if (c > 9)
       c += 'A' - 10;
    else
       c += '0';
    
    putc ( c );
}

void send_hex (uint8_t c)
{
    send_digit (c >> 4);
    send_digit (c & 0x0F);
}

// Send ROM string out PC UART.
#pragma save
#pragma NOAREGS
void start_tx_rslt (uint8r_t *pc) small reentrant
{
    uint8_t c;
    c = *pc;
    while (c)
    {
        putc ( c );
        ++pc;
        c = *pc;
    }
}
#pragma restore

#undef NULL
#undef LF
#undef CRET
#define NULL    0x00
#define LF      0x0A     // LINE FEED
#define CRET    0x0D     // CARRIAGE RETURN
static uint8r_t v_crlf[] = { CRET, LF, NULL };
#pragma save
#pragma NOAREGS
void send_crlf (void) small reentrant    // Send <CR><LF> out PC UART.
{
    start_tx_rslt (v_crlf);
}
#pragma restore

// Get next hexadecimal digit.
#undef CASE_
#define CASE_   0x20
static uint8_t rcv_digit (void)                     
{
    uint8_t c;

    do {
        c = getc ();
        if (io_timeout)
            return 0;
    } while (!isxdigit(c));

    c -= '0';              // '0' mapped to  0;

    if (c >= 10)
    {
        c &= ~CASE_;
        c -= 'A' - '0' - 10;            // 'A' mapped to 10.
    }

    return (c);
}

uint8_t rcv_hex (void)    // Convert ascii hexdecimal byte to binary 
{
    return ((rcv_digit () << 4) | rcv_digit ());
}

/***************************************************************************
 * History:
 * $Log: io_lite.c,v $
 * Revision 1.12  2006/03/10 00:03:40  tvander
 * Now selects its BAUD rate using DIO_8 for the 6520.
 *
 * Revision 1.11  2006/09/09 01:09:37  gmikef
 * *** empty log message ***
 *
 * Revision 1.10  2006/08/16 01:43:08  tvander
 * Only send one XOFF
 *
 * Revision 1.9  2006/08/09 00:56:34  tvander
 * *** empty log message ***
 *
 * Revision 1.8  2006/07/28 02:45:23  tvander
 * Fixed missing XON
 *
 * Revision 1.7  2006/07/25 00:27:59  tvander
 * Added timeout
 *
 * Revision 1.6  2006/07/19 01:53:08  tvander
 * Modified to do XON/XOFF
 *
 * Revision 1.5  2006/07/18 20:32:19  tvander
 * Quick & Dirty XON/XOFF scheme
 *
 * Revision 1.4  2006/07/07 00:53:44  tvander
 * Modified lightweight IO to change baudrates to adapt to clock changes.
 *
 * Revision 1.3  2006/06/08 18:24:55  tvander
 * Removed call to background
 *
 * Revision 1.2  2006/06/06 03:56:27  tvander
 * A lame substitute for io.c, but very compact.
 *
 * Revision 1.1  2006/05/27 01:35:05  tvander
 * *** empty log message ***
 *
 *
 * 2006 May 25; First Version. 
 * Copyright (C) 2006 Teridian Semiconductor Corp. All Rights Reserved.    *
 * this program is fully protected by the United States copyright          *
 * laws and is the property of Teridian Semiconductor Corporation.         *
 ***************************************************************************/
#endif