Yifei Teng / MODI2C

Improvements to Olieman's MODI2C library. Supports calls from IRQ.

Dependencies:   FPointer

Dependents:   FreeIMU FreeIMU_external_magnetometer FreeIMU

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MODI2C Class Reference
Public Member Functions

MODI2C Class Reference

Library that allows interrupt driven communication with I2C devices. More...

#include <MODI2C.h>

Public Member Functions

 MODI2C (PinName sda, PinName scl)
 Constructor.
int write (int address, char *data, int length, uint32_t(*function)(uint32_t)=NULL, void *pass_to_irq=NULL, bool repeated=false, int *status=NULL)
 Write data on the I2C bus.
int read_nb (int address, char *data, int length, uint32_t(*function)(uint32_t)=NULL, void *pass_to_irq=NULL, bool repeated=false, int *status=NULL)
 Read data non-blocking from the I2C bus.
int read (int address, char *data, int length, bool repeated=false)
 Read data from the I2C bus.
void frequency (int hz)
 Sets the I2C bus frequency.
void start (void)
 Creates a start condition on the I2C bus.
void stop (void)
 Creates a stop condition on the I2C bus.

Detailed Description

Library that allows interrupt driven communication with I2C devices.

For now this is all in beta, so if you got weird results while the mbed I2C library works, it is probably my fault. Similar to googles definition of beta, it is unlikely it will ever come out of beta.

Example: 

 #include "mbed.h"
 #include "MODI2C.h"
 #include "MPU6050.h"

 Serial pc(USBTX, USBRX); // tx, rx
 MODI2C mod(p9, p10);

 int main() {
     char registerAdd = MPU6050_WHO_AM_I_REG;
     char registerResult;
     int status;

     while (1) {
         mod.write(MPU6050_ADDRESS*2, &registerAdd, 1, true);
         mod.read_nb(MPU6050_ADDRESS*2, &registerResult, 1, &status);

         while (!status) wait_us(1);
         pc.printf("Register holds 0x%02X\n\r", registerResult);
         wait(2);
     }
 }

Definition at line 78 of file MODI2C.h.

Constructor & Destructor Documentation

MODI2C ( PinName  sda,
PinName  scl 
)

Constructor.

Parameters:
sda- mbed pin to use for the SDA I2C line.
scl- mbed pin to use for the SCL I2C line.

Definition at line 12 of file MODI2C.cpp.

Member Function Documentation

void frequency ( int  hz )

Sets the I2C bus frequency.

Parameters:
hz- the bus frequency in herz

Definition at line 160 of file MODI2C.cpp.

int read ( int  address,
char *  data,
int  length,
bool  repeated = false 
)

Read data from the I2C bus.

This function should should be a drop-in replacement for the standard mbed function.

Parameters:
address- I2C address of the slave (7 bit address << 1).
data- pointer to byte array where the data will be stored
length- amount of bytes that need to be received
repeated- determines if it should end with a stop condition
return- returns zero on success, LPC status code on failure

Definition at line 110 of file MODI2C.cpp.

int read_nb ( int  address,
char *  data,
int  length,
uint32_t(*)(uint32_t)  function = NULL,
void *  pass_to_irq = NULL,
bool  repeated = false,
int *  status = NULL 
)

Read data non-blocking from the I2C bus.

Reads data from the I2C bus, completely non-blocking. Aditionally it will always return zero, since it does not wait to see how the transfer goes. A pointer to an integer can be added as argument which returns the status.

Parameters:
address- I2C address of the slave (7 bit address << 1).
data- pointer to byte array where the data will be stored
length- amount of bytes that need to be received
function- pointer to a callback function of the form "uint32_t func(uint32_t)"
pass_to_irq- what to pass to the callback function as parameter
repeated- determines if it should end with a stop condition
status- (optional) pointer to integer where the final status code of the I2C transmission is placed. (0x58 is success)
return- returns zero

Definition at line 75 of file MODI2C.cpp.

void start ( void   )

Creates a start condition on the I2C bus.

If you use this function you probably break something (but mbed also had it public)

Definition at line 152 of file MODI2C.cpp.

void stop ( void   )

Creates a stop condition on the I2C bus.

If you use this function you probably break something (but mbed also had it public)

Definition at line 156 of file MODI2C.cpp.

int write ( int  address,
char *  data,
int  length,
uint32_t(*)(uint32_t)  function = NULL,
void *  pass_to_irq = NULL,
bool  repeated = false,
int *  status = NULL 
)

Write data on the I2C bus.

This function should generally be a drop-in replacement for the standard mbed write function. However this function is completely non-blocking, so it barely takes time. This can cause different behavior. Everything else is similar to read_nb.

Parameters:
address- I2C address of the slave (7 bit address << 1).
data- pointer to byte array that holds the data
length- amount of bytes that need to be sent
function- pointer to a callback function of the form "uint32_t func(uint32_t)"
pass_to_irq- what to pass to the callback function as parameter
repeated- determines if it should end with a stop condition (default false)
status- (optional) pointer to integer where the final status code of the I2C transmission is placed. (0x28 is success)
return- returns zero

Definition at line 27 of file MODI2C.cpp.

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