i2c_h8s_edosk2674.c

ecos移植到R8H系列的源码。源码包来自http://www.cetoni.de/develop/develop_ecosh8s_en.html

//==========================================================================
//
//      devs/wallclock/h8s/edosk2674/include/i2c_h8s_edosk2674.c
//
//      EDOSK2674 I2C interface
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
// Copyright (C) 2003 Gary Thomas
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   Uwe Kindler
// Contributors:Uwe Kindler
// Date:        2003-11-26
// Purpose:     EDOSK2674 I2C interface - the I2C interface is only required
//              for interfacing the Dallas DS1672 RTC. Therefore we make it
//              part of the EDOSK2674 RTC drivers
//####DESCRIPTIONEND####
//==========================================================================


//===========================================================================
//                                 INCLUDES
//===========================================================================
#include <cyg/io/ds1672.h>              // ds1672 I2C interface and register definitions
#include <cyg/hal/var_arch.h>           // h8s2674 port io
#include <cyg/hal/hal_io.h>             // generic H8S register access
#include <cyg/hal/plf_intr.h>           // HAL_DELAY_US()


//===========================================================================
//                                 DEFINES
//===========================================================================
#define P3DDR_SDA_READ       (0x3A)                    // read from sda register 
#define P3DDR_SDA_WRITE      (0x3A | CYGARC_P3_I2C_SDA)// write to sda register


//===========================================================================
//                         READ SDA FROM I2C BUS
// DESCRIPTTION:
//      Reads pin state of SDA pin on port 3
//
// RETURNS:
//      Pin state of SDA pin on port 3
//===========================================================================
cyg_uint8 i2c_sda_rd(void)
{
    cyg_uint8 tmp;
    
    
    HAL_WRITE_UINT8(CYGARC_P3DDR, P3DDR_SDA_READ);  // set P32 as input
    HAL_READ_UINT8(CYGARC_PORT3, tmp);              // read port 3 pin states
    return (tmp & CYGARC_P3_I2C_SDA) >> 2;          // return pin state
}


//===========================================================================
//                         WRITE TO I2C SDA LINE
// DESCRIPTTION:
//     Sets pin state of SDA pin on port 3
//
// ARGUMENTS:
//     'sdaval'  Is 0 or 1 
//===========================================================================
void i2c_sda_wr(cyg_uint8 sdaval)
{
    cyg_uint8 tmp;
    
    
    HAL_WRITE_UINT8(CYGARC_P3DDR, P3DDR_SDA_WRITE);  // set P32 as output 
    HAL_READ_UINT8(CYGARC_P3DR, tmp);                // read P3DR value  
    if (sdaval > 0)
    {
        tmp |= CYGARC_P3_I2C_SDA;
    }
    else
    {
        tmp &= ~CYGARC_P3_I2C_SDA;
    }
    HAL_WRITE_UINT8(CYGARC_P3DR, tmp);                // write P3DR value  
}


//===========================================================================
//                       WRITE TO I2C SCL LINE
// DESCRIPTTION:
//     Sets pin state of SCL pin on port 3
//
// ARGUMENTS:
//     'sclval'  Is 0 or 1 
//===========================================================================
void i2c_scl_wr(cyg_uint8 sclval)
{
    cyg_uint8 tmp;
    

    HAL_READ_UINT8(CYGARC_P3DR, tmp);                // read P3DR value  
    if (sclval > 0)
    {
        tmp |= CYGARC_P3_I2C_SCL;
    }
    else
    {
        tmp &= ~CYGARC_P3_I2C_SCL;
    }
    HAL_WRITE_UINT8(CYGARC_P3DR, tmp);                // write P3DR value  
}


//===========================================================================
//                       CREATE I2C BUS START CONDITION
// DESCRIPTTION:
//     A change in the state of the data line from high to low, while clock
//     line is high defines a start condition
//===========================================================================
void i2c_start(void)
{      
    i2c_sda_wr(1);
    i2c_scl_wr(1);
    i2c_sda_wr(0);
}


//===========================================================================
//                       CREATE I2C BUS STOP CONDITION
// DESCRIPTION:
//     A change in the state of the data line from low to high, while clock
//     line is high defines a stop condition
//===========================================================================
void i2c_stop(void)
{
    i2c_sda_wr(0);
    HAL_DELAY_US(4);
    i2c_scl_wr(0);
    HAL_DELAY_US(4);
    i2c_sda_wr(1);
}


//===========================================================================
//                       READ BYTE FROM I2C BUS
// DESCRIPTTION:
//     Read one single byte from I2C bus
//
// ARGUMENTS:
//     'ackn'   Select if acknowledge should be sent (I2C_ACK or I2C_NACK)
//
// RETURNS:
//     Byte read from I2C bus
//===========================================================================
cyg_uint8 i2c_byte_rd(cyg_uint8 ackn)
{
    cyg_uint8 i;
    cyg_uint8 data;
    cyg_uint8 sda;
    
    data = 0;
    i2c_sda_wr(1);   // let go of SDA line
    //
    // now read one byte from sda - read msbfirst
    //
    for (i = 0; i < 8; i++)
    {
        i2c_scl_wr(0);
        HAL_DELAY_US(2);
        //
        // set SCL high and read data 
        //
        i2c_scl_wr(1);
        HAL_DELAY_US(2);
        sda = i2c_sda_rd();                    
        data   <<= 1;
        data   |=  sda;
        i2c_scl_wr(1);
        //
        // data is read - pull SCL down again
        //
        i2c_scl_wr(0);     
    }
    //
    // hold sda low for acknowledge
    //
    i2c_sda_wr(ackn);
    i2c_scl_wr(0);
    HAL_DELAY_US(4);
    i2c_scl_wr(1);
    HAL_DELAY_US(4);
    if (I2C_NACK == ackn)
    {
        i2c_sda_wr(1);     // next cycle is reset
    } 
    i2c_scl_wr(0);
    HAL_DELAY_US(4);
    //
    // release sda line
    //
    i2c_sda_wr(1);
    
    return data;
}


//===========================================================================
//                          WRITE BYTE TO I2C BUS
// DESCRIPTTION:
//     Writes one single byte to I2C bus
//
// ARGUMENTS:
//     'data'   Data byte to be written to I2C bus
//===========================================================================
void i2c_byte_wr(cyg_uint8 data)
{
    cyg_uint8 i;
    
    
    i2c_scl_wr(0);
    for (i = 0; i < 8; i++)
    {
        //
        // send the msbits first
        //
        if (data & 0x80)
        {
            i2c_sda_wr(1);
        }
        else
        {
            i2c_sda_wr(0);
        }
        i2c_scl_wr(0);
        HAL_DELAY_US(4);
        i2c_scl_wr(1);
        HAL_DELAY_US(4);
        i2c_scl_wr(0);
        HAL_DELAY_US(4);
        data <<= 1;
    }    
    //
    // Release the sda line
    //
    i2c_sda_wr(1);
    HAL_DELAY_US(4);
    i2c_scl_wr(0);
    HAL_DELAY_US(4);
    i2c_scl_wr(1);
    HAL_DELAY_US(4);
    i2c_scl_wr(0);
    HAL_DELAY_US(4);
}


//--------------------------------------------------------------------------
// End of i2c_h8s_edosk2674.h