maxqi2c.h

第一块板是飞思卡尔的MX9823ADS评估板

/* 
 * maxqi2c.h v0.1
 *
 * Author: Paul Holden
 *
 * Library function for performing I2C communication
 *
 * See the associated Maxim Appnote for documentation
 *
 * NOTE: THE TIMING IN THIS CODE ASSUMES THE MAXQ2000
 *       IS RUNNING FROM A 20MHZ CLOCK AND THE
 *       OPTIMIZER IS SET TO RUN AT THE SETTING 3
 *
 * HISTORY
 *   v0.1 - June 1st, 2005: File created
 *
 */
#ifndef __MAXQI2C_H__
#define __MAXQI2C_H__

#include "iomaxq200x.h"

/* USER MUST CUSTOMIZE THE FOLLOWING DEFINE STMTS - START */
  // Enter the port used for SDA and SCL
  #define SDA_PORT               0
  #define SCL_PORT               0

  // Enter the pin used for SDA and SCL
  #define SDA_PORT_BIT           0
  #define SCL_PORT_BIT           1

  // Uncomment one of these define statements to select I2C bus speed
  #define I2C_400_KHZ
  //#define I2C_100_KHZ
  
  // Comment out the following define statement to disable clock
  // stretching in i2cRecv()
  #define I2C_CLOCK_STRETCHING
/* USER MUST CUSTOMIZE THE FOLLOWING DEFINE STMTS - END   */

// The possible values for the i2cDataTerm variable
// i2cSend
#define I2C_TERM_NONE           0x00
#define I2C_TERM_STOP           0x01
//i2cRecv (I2C_TERM_NONE will work but is not recommended during an i2cRecv)
#define I2C_TERM_ACK            0x02
#define I2C_TERM_NACK_AND_STOP  0x03

// The possible return values from the i2cSend and i2cRecv functions
#define I2C_XMIT_FAILED         0x00
#define I2C_XMIT_OK             0x01

// The parameters to the functions:
//
//    i2cIsAddrPresent()
//    i2cSend()
//    i2cRecv
//
// See the comments to the actual functions for the
// usage of these variables.
//
// These are made global and extern to allow any module
// in the application to edit them without the need to
// send them as parameters to the function. This design
// decision was made to increase the speed of the system.
extern volatile unsigned char  *i2cData;
extern volatile unsigned int    i2cDataLen;
extern volatile unsigned char   i2cDataAddr;
extern volatile unsigned char   i2cDataTerm;

/*
 * i2cInit()
 *
 * Params:
 *    none
 *
 * Returns:
 *    nothing
 *
 * Description: Initializes the pins that are used as SDA
 *    and SCL. This function must be called before any other
 *    of the i2c functions are called
 *
 */
void i2cInit();
/*
 * i2cIsAddrPresent()
 *
 * Params:
 *    i2cDataAddr (global unsigned char): The i2c address
 *
 * Returns:
 *    unsigned char: I2C_XMIT_FAILED or I2C_XMIT_OK
 *
 * Description: Send the i2c address (with a write indicator)
 *    to see if a slave sends an acknowledge. The address send
 *    is taken from the i2cDataAddr global and the result
 *    should be compared with I2C_XMIT_FAILED and I2C_XMIT_OK
 *    to determine if the slave was present. The format is
 *
 *    [S] [ADDR+W] [A] [P]
 *
 */
unsigned char i2cIsAddrPresent();
/*
 * i2cSend()
 *
 * Params:
 *   *i2cData     (global unsigned char *): Pointer to the i2c data bytes
 *    i2cDataLen  (global unsigned char)  : The i2c data length (not incl addr)
 *    i2cDataAddr (global unsigned char)  : The i2c address
 *    i2cDataTerm (global unsigned char)  : The i2c transmit ternimation
 *
 * Returns:
 *    unsigned char: I2C_XMIT_FAILED or I2C_XMIT_OK
 *
 * Description: Sends i2c data to a slave. The format is 
 *
 *   [S] [ADDR+W] [A] [DATA0] [A] [DATA1] [A] ... [DATA LEN-1] [A] [TERM]
 *                 ^-Slave     ^-Slave     ^-Slave              ^-Slave
 *
 * NOTE1: This function allows the header ([ADDR+W] [A]) not to be
 *    sent by setting the i2cDataAddr to 0x00.
 *
 * NOTE2: This function allows a custom termination by setting the
 *    i2cDataTerm to I2C_TERM_NONE (no termination) or I2C_TERM_STOP
 *    (an actual NACK then a P signal on the I2C bus, where P is a
 *    stop signal).
 *
 * NOTE3: It is the responsibility of the user to ensure that the
 *    array pointed to by i2cData (unsigned char *) has i2cDataLen
 *    data bytes in it.
 *
 */
unsigned char i2cSend();
/*
 * i2cRecv()
 *
 * Params:
 *   *i2cData     (global unsigned char *): Pointer to the i2c data bytes
 *    i2cDataLen  (global unsigned char)  : The i2c data length (not incl addr)
 *    i2cDataAddr (global unsigned char)  : The i2c address
 *    i2cDataTerm (global unsigned char)  : The i2c transmit ternimation
 *
 * Returns:
 *    unsigned char: I2C_XMIT_FAILED or I2C_XMIT_OK
 *
 * Description: Receives i2c data from a slave. The format is 
 *
 *   [S] [ADDR+R] [A] [DATA0] [A] [DATA1] [A] ... [DATA LEN-1] [TERM]
 *                 ^-Slave     ^-Master    ^-Master             
 *
 * NOTE1: This function allows the header ([ADDR+R] [A]) not to be
 *    sent by setting the i2cDataAddr to 0x00.
 *
 * NOTE2: This function allows a custom termination by setting the
 *    i2cDataTerm to I2C_TERM_NONE (no termination), I2C_TERM_ACK
 *    (an A), or a I2C_TERM_NACK_AND_STOP (an actual NACK then a P
 *    signal on the I2C bus, where P is a stop signal).
 *
 * NOTE3: It is the responsibility of the user to ensure that the
 *    array pointed to by i2cData (unsigned char *) has i2cDataLen
 *    data bytes available.
 *
 */
unsigned char i2cRecv();

// THE PROGRAMMER SHOULD NOT EDIT ANYTHING BELOW THIS LINE

#define PORT_OUT_BIT(A,B)      PO## A ##_bit.bit## B
#define PORT_DIR_BIT(A,B)      PD## A ##_bit.bit## B
#define PORT_IN_BIT(A,B)       PI## A ##_bit.bit## B

// Macros required for double expansion
#define PORT_OUT_BIT_EXP(A,B)  PORT_OUT_BIT(A,B)
#define PORT_DIR_BIT_EXP(A,B)  PORT_DIR_BIT(A,B)
#define PORT_IN_BIT_EXP(A,B)   PORT_IN_BIT(A,B)

#define SDA_PULLUP             PORT_OUT_BIT_EXP(SDA_PORT,SDA_PORT_BIT)
#define SCL_PULLUP             PORT_OUT_BIT_EXP(SCL_PORT,SCL_PORT_BIT)
#define SDA                    PORT_DIR_BIT_EXP(SDA_PORT,SDA_PORT_BIT)
#define SCL                    PORT_DIR_BIT_EXP(SCL_PORT,SCL_PORT_BIT)
#define SDA_IN                 PORT_IN_BIT_EXP(SDA_PORT,SDA_PORT_BIT)
#define SCL_IN                 PORT_IN_BIT_EXP(SCL_PORT,SCL_PORT_BIT)

#endif