Frank Vannieuwkerke / KL25Z_I2C_busreset

Tool to recover from an I2C bus lockup on the KL25Z

Dependents:   Ejerc_slave_I2c

This tool allows you to recover from an I2C bus lockup on I2C0 (PTE24, PTE25) and I2C1 (PTE0, PTE1).
The reset is only carried out when the corresponding I2C bus is enabled.

Add following code to your program :

#include "I2C_busreset.h"
...
...
int main (void)
{
    I2C_busreset();
    ....

I2C_busreset.cpp

Committer:
frankvnk
Date:
2014-02-19
Revision:
0:e9beb537cf77

File content as of revision 0:e9beb537cf77:

/**************************************************************************************************
 *****                                                                                        *****
 *****  Name: KL25Z I2C_busreset.cpp                                                          *****
 *****  Date: 24/11/2013                                                                      *****
 *****  Auth: Frank Vannieuwkerke                                                             *****
 *****  Func: library for unblocking I2C bus on KL25Z board                                   *****
 *****  Info: MPL3115A2-AN4481                                                                *****
 **************************************************************************************************/

#include "I2C_busreset.h"

void I2C_busreset(void)
{
    if((PORTE->PCR[1] & PORT_PCR_MUX(6)) && (PORTE->PCR[0] & PORT_PCR_MUX(6)))
    {
        I2C1->C1 &= 0x7f;                 // Disable I2C1 bus
        PORTE->PCR[1] = PORT_PCR_MUX(1);  // PTE1 Alt1 (pin)
        PORTE->PCR[0] = PORT_PCR_MUX(1);  // PTE0 Alt1 (pin)
        if((PTE->PDIR & 0x3) != 3)        // When PTE0 / PTE1 are not 1 : I2C1 bus lock-up
        {
            PTE->PDDR |= 0x2;             // Set PTE1 as a GPIO output so we can bit bang it
            PTE->PDOR |= 0x2;             // Set PTE1 (SCL) pin high;
            wait_ms(1);
            while(!(PTE->PDIR & 0x1))     // bit bang SCL until the offending device releases the bus
            {   
                PTE->PDOR &= 0xfffffffd;  // Set PTE1 (SCL) pin low;
                wait_ms(1);
                PTE->PDOR |= 0x2;         // Set PTE1 (SCL) pin high;
                wait_ms(1);
            }
        }
        // Reinstate I2C1 bus pins
        PORTE->PCR[1] = PORT_PCR_MUX(6);  // PTE1 Alt6 (SCL)
        PORTE->PCR[0] = PORT_PCR_MUX(6);  // PTE0 Alt6 (SDA)
        I2C1->C1 |= 0x80;                 // Enable I2C1 bus
    }

    if((PORTE->PCR[24] & PORT_PCR_MUX(5)) && (PORTE->PCR[25] & PORT_PCR_MUX(5)))
    {
        I2C0->C1 &= 0x7f;                 // Disable I2C0 bus
        PORTE->PCR[24] = PORT_PCR_MUX(1); // PTE24 Alt1 (pin)
        PORTE->PCR[25] = PORT_PCR_MUX(1); // PTE25 Alt1 (pin)
        if((PTE->PDIR & 0x03000000) != 0x03000000)  // When PTE24 / PTE25 are not 1 : I2C0 bus lock-up
        {
            PTE->PDDR |= 0x01000000;      // Set PTE24 as a GPIO output so we can bit bang it
            PTE->PDOR |= 0x01000000;      // Set PTE24 (SCL) pin high;
            wait_ms(1);
            while(!(PTE->PDIR & 0x1))     // bit bang SCL until the offending device releases the bus
            {   
                PTE->PDOR &= 0xfeffffff;  // Set PTE24 (SCL) pin low;
                wait_ms(1);
                PTE->PDOR |= 0x01000000;  // Set PTE24 (SCL) pin high;
                wait_ms(1);
            }
        }
        // Reinstate I2C0 bus pins
        PORTE->PCR[24] = PORT_PCR_MUX(5); // PTE24 Alt6 (SCL)
        PORTE->PCR[25] = PORT_PCR_MUX(5); // PTE25 Alt6 (SDA)
        I2C0->C1 |= 0x80;                 // Enable I2C0 bus
    }
}