This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

CCS/TM4C1294NCPDT: I2C Slave Interrupt Example works only with CCS Debugging

Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: EK-TM4C1294XL,

Tool/software: Code Composer Studio

Hi!

I have bought the EK-TM4C1294XL Launchpad with the TM4C1294NCPDT chip. I'd like to setup I2C communication between different devices. From the TivaWare_C_Series-2.1.4.178 examples I used the I2C "slave_receive_int.c" file and set the "I2C0SlaveIntHandler" in the "startup_css.c" interrupt vector table for the I2C0 interrupt. In Code Composer Studio 7 I clicked the Debug-Button to check the functionality of this code, which works fine. Step mode and also normal mode with and without breakpoints. If the Debug-Mode is stopped and the Launchpad is reseted by the onboard reset button, the I2C example hangs after the UART print "sending", probably the while loop for waiting until the slave interrupt occured and the flag is set. I turned the compiler optimizer off.

I don't understand what the difference is between debug mode and normal mode with this setup. What I am missing here?

Best regards

startup_css.c
//*****************************************************************************
//
// startup_ccs.c - Startup code for use with TI's Code Composer Studio.
//
// Copyright (c) 2013-2016 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
// 
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
// 
// This is part of revision 2.1.3.156 of the EK-TM4C1294XL Firmware Package.
//
//*****************************************************************************

#include <stdint.h>
#include "inc/hw_nvic.h"
#include "inc/hw_types.h"

//*****************************************************************************
//
// Forward declaration of the default fault handlers.
//
//*****************************************************************************
void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);

//*****************************************************************************
//
// External declaration for the reset handler that is to be called when the
// processor is started
//
//*****************************************************************************
extern void _c_int00(void);

//*****************************************************************************
//
// Linker variable that marks the top of the stack.
//
//*****************************************************************************
extern uint32_t __STACK_TOP;

//*****************************************************************************
//
// External declaration for the interrupt handler used by the application.
//
//*****************************************************************************
extern void I2C0SlaveIntHandler(void);

//*****************************************************************************
//
// The vector table.  Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000 or at the start of
// the program if located at a start address other than 0.
//
//*****************************************************************************
#pragma DATA_SECTION(g_pfnVectors, ".intvecs")
void (* const g_pfnVectors[])(void) =
{
    (void (*)(void))((uint32_t)&__STACK_TOP),
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    IntDefaultHandler,                      // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // SVCall handler
    IntDefaultHandler,                      // Debug monitor handler
    0,                                      // Reserved
    IntDefaultHandler,                      // The PendSV handler
    IntDefaultHandler,                      // The SysTick handler
    IntDefaultHandler,                      // GPIO Port A
    IntDefaultHandler,                      // GPIO Port B
    IntDefaultHandler,                      // GPIO Port C
    IntDefaultHandler,                      // GPIO Port D
    IntDefaultHandler,                      // GPIO Port E
    IntDefaultHandler,                      // UART0 Rx and Tx
    IntDefaultHandler,                      // UART1 Rx and Tx
    IntDefaultHandler,                      // SSI0 Rx and Tx
    I2C0SlaveIntHandler,                   // I2C0 Master and Slave
    IntDefaultHandler,                      // PWM Fault
    IntDefaultHandler,                      // PWM Generator 0
    IntDefaultHandler,                      // PWM Generator 1
    IntDefaultHandler,                      // PWM Generator 2
    IntDefaultHandler,                      // Quadrature Encoder 0
    IntDefaultHandler,                      // ADC Sequence 0
    IntDefaultHandler,                      // ADC Sequence 1
    IntDefaultHandler,                      // ADC Sequence 2
    IntDefaultHandler,                      // ADC Sequence 3
    IntDefaultHandler,                      // Watchdog timer
    IntDefaultHandler,                      // Timer 0 subtimer A
    IntDefaultHandler,                      // Timer 0 subtimer B
    IntDefaultHandler,                      // Timer 1 subtimer A
    IntDefaultHandler,                      // Timer 1 subtimer B
    IntDefaultHandler,                      // Timer 2 subtimer A
    IntDefaultHandler,                      // Timer 2 subtimer B
    IntDefaultHandler,                      // Analog Comparator 0
    IntDefaultHandler,                      // Analog Comparator 1
    IntDefaultHandler,                      // Analog Comparator 2
    IntDefaultHandler,                      // System Control (PLL, OSC, BO)
    IntDefaultHandler,                      // FLASH Control
    IntDefaultHandler,                      // GPIO Port F
    IntDefaultHandler,                      // GPIO Port G
    IntDefaultHandler,                      // GPIO Port H
    IntDefaultHandler,                      // UART2 Rx and Tx
    IntDefaultHandler,                      // SSI1 Rx and Tx
    IntDefaultHandler,                      // Timer 3 subtimer A
    IntDefaultHandler,                      // Timer 3 subtimer B
    IntDefaultHandler,                    // I2C1 Master and Slave
    IntDefaultHandler,                      // CAN0
    IntDefaultHandler,                      // CAN1
    IntDefaultHandler,                      // Ethernet
    IntDefaultHandler,                      // Hibernate
    IntDefaultHandler,                      // USB0
    IntDefaultHandler,                      // PWM Generator 3
    IntDefaultHandler,                      // uDMA Software Transfer
    IntDefaultHandler,                      // uDMA Error
    IntDefaultHandler,                      // ADC1 Sequence 0
    IntDefaultHandler,                      // ADC1 Sequence 1
    IntDefaultHandler,                      // ADC1 Sequence 2
    IntDefaultHandler,                      // ADC1 Sequence 3
    IntDefaultHandler,                      // External Bus Interface 0
    IntDefaultHandler,                      // GPIO Port J
    IntDefaultHandler,                      // GPIO Port K
    IntDefaultHandler,                      // GPIO Port L
    IntDefaultHandler,                      // SSI2 Rx and Tx
    IntDefaultHandler,                      // SSI3 Rx and Tx
    IntDefaultHandler,                      // UART3 Rx and Tx
    IntDefaultHandler,                      // UART4 Rx and Tx
    IntDefaultHandler,                      // UART5 Rx and Tx
    IntDefaultHandler,                      // UART6 Rx and Tx
    IntDefaultHandler,                      // UART7 Rx and Tx
    IntDefaultHandler,                      // I2C2 Master and Slave
    IntDefaultHandler,                      // I2C3 Master and Slave
    IntDefaultHandler,                      // Timer 4 subtimer A
    IntDefaultHandler,                      // Timer 4 subtimer B
    IntDefaultHandler,                      // Timer 5 subtimer A
    IntDefaultHandler,                      // Timer 5 subtimer B
    IntDefaultHandler,                      // FPU
    0,                                      // Reserved
    0,                                      // Reserved
    IntDefaultHandler,                      // I2C4 Master and Slave
    IntDefaultHandler,                      // I2C5 Master and Slave
    IntDefaultHandler,                      // GPIO Port M
    IntDefaultHandler,                      // GPIO Port N
    0,                                      // Reserved
    IntDefaultHandler,                      // Tamper
    IntDefaultHandler,                      // GPIO Port P (Summary or P0)
    IntDefaultHandler,                      // GPIO Port P1
    IntDefaultHandler,                      // GPIO Port P2
    IntDefaultHandler,                      // GPIO Port P3
    IntDefaultHandler,                      // GPIO Port P4
    IntDefaultHandler,                      // GPIO Port P5
    IntDefaultHandler,                      // GPIO Port P6
    IntDefaultHandler,                      // GPIO Port P7
    IntDefaultHandler,                      // GPIO Port Q (Summary or Q0)
    IntDefaultHandler,                      // GPIO Port Q1
    IntDefaultHandler,                      // GPIO Port Q2
    IntDefaultHandler,                      // GPIO Port Q3
    IntDefaultHandler,                      // GPIO Port Q4
    IntDefaultHandler,                      // GPIO Port Q5
    IntDefaultHandler,                      // GPIO Port Q6
    IntDefaultHandler,                      // GPIO Port Q7
    IntDefaultHandler,                      // GPIO Port R
    IntDefaultHandler,                      // GPIO Port S
    IntDefaultHandler,                      // SHA/MD5 0
    IntDefaultHandler,                      // AES 0
    IntDefaultHandler,                      // DES3DES 0
    IntDefaultHandler,                      // LCD Controller 0
    IntDefaultHandler,                      // Timer 6 subtimer A
    IntDefaultHandler,                      // Timer 6 subtimer B
    IntDefaultHandler,                      // Timer 7 subtimer A
    IntDefaultHandler,                      // Timer 7 subtimer B
    IntDefaultHandler,                      // I2C6 Master and Slave
    IntDefaultHandler,                      // I2C7 Master and Slave
    IntDefaultHandler,                      // HIM Scan Matrix Keyboard 0
    IntDefaultHandler,                      // One Wire 0
    IntDefaultHandler,                      // HIM PS/2 0
    IntDefaultHandler,                      // HIM LED Sequencer 0
    IntDefaultHandler,                      // HIM Consumer IR 0
    IntDefaultHandler,                      // I2C8 Master and Slave
    IntDefaultHandler,                      // I2C9 Master and Slave
    IntDefaultHandler                       // GPIO Port T
};

//*****************************************************************************
//
// This is the code that gets called when the processor first starts execution
// following a reset event.  Only the absolutely necessary set is performed,
// after which the application supplied entry() routine is called.  Any fancy
// actions (such as making decisions based on the reset cause register, and
// resetting the bits in that register) are left solely in the hands of the
// application.
//
//*****************************************************************************
void
ResetISR(void)
{
    //
    // Jump to the CCS C initialization routine.  This will enable the
    // floating-point unit as well, so that does not need to be done here.
    //
    __asm("    .global _c_int00\n"
          "    b.w     _c_int00");
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a NMI.  This
// simply enters an infinite loop, preserving the system state for examination
// by a debugger.
//
//*****************************************************************************
static void
NmiSR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
    //
    // Enter an infinite loop.
    //
    while(1)
    {
    }
}

//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt.  This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
IntDefaultHandler(void)
{
    //
    // Go into an infinite loop.
    //
    while(1)
    {
    }
}

slave_receive_int.c
//*****************************************************************************
//
// slave_receive_int.c - Example demonstrating a simple I2C master message
//                       transmission using a slave interrupt when data is
//                       received.
//
// Copyright (c) 2010-2017 Texas Instruments Incorporated.  All rights reserved.
// Software License Agreement
// 
//   Redistribution and use in source and binary forms, with or without
//   modification, are permitted provided that the following conditions
//   are met:
// 
//   Redistributions of source code must retain the above copyright
//   notice, this list of conditions and the following disclaimer.
// 
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the  
//   distribution.
// 
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// 
// This is part of revision 2.1.4.178 of the Tiva Firmware Development Package.
//
//*****************************************************************************

#include <stdbool.h>
#include <stdint.h>
#include "inc/hw_i2c.h"
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/gpio.h"
#include "driverlib/i2c.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"

//*****************************************************************************
//
//! \addtogroup i2c_examples_list
//! <h1>Slave Receive Interrupt (slave_receive_int)</h1>
//!
//! This example shows how to configure a receive interrupt on the slave
//! module.  This includes setting up the I2C0 module for loopback mode as well
//! as configuring the master and slave modules.  Loopback mode internally
//! connects the master and slave data and clock lines together.  The address
//! of the slave module is set to a value so it can receive data from the
//! master.
//!
//! This example uses the following peripherals and I/O signals.  You must
//! review these and change as needed for your own board:
//! - I2C0 peripheral
//! - GPIO Port B peripheral (for I2C0 pins)
//! - I2C0SCL - PB2
//! - I2C0SDA - PB3
//!
//! The following UART signals are configured only for displaying console
//! messages for this example.  These are not required for operation of I2C.
//! - UART0 peripheral
//! - GPIO Port A peripheral (for UART0 pins)
//! - UART0RX - PA0
//! - UART0TX - PA1
//!
//! This example uses the following interrupt handlers.  To use this example
//! in your own application you must add these interrupt handlers to your
//! vector table.
//! - INT_I2C0 - I2C0SlaveIntHandler
//
//*****************************************************************************

//*****************************************************************************
//
// Set the address for slave module. This is a 7-bit address sent in the
// following format:
//                      [A6:A5:A4:A3:A2:A1:A0:RS]
//
// A zero in the R/S position of the first byte means that the master
// transmits (sends) data to the selected slave, and a one in this position
// means that the master receives data from the slave.
//
//*****************************************************************************
#define SLAVE_ADDRESS           0x3C

//*****************************************************************************
//
// Global variable to hold the I2C data that has been received.
//
//*****************************************************************************
static uint32_t g_ui32DataRx;

//*****************************************************************************
//
// This is a flag that gets set in the interrupt handler to indicate that an
// interrupt occurred.
//
//*****************************************************************************
static bool g_bIntFlag = false;

//*****************************************************************************
//
// This function sets up UART0 to be used for a console to display information
// as the example is running.
//
//*****************************************************************************
void
InitConsole(void)
{
    //
    // Enable GPIO port A which is used for UART0 pins.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Configure the pin muxing for UART0 functions on port A0 and A1.
    // This step is not necessary if your part does not support pin muxing.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);

    //
    // Enable UART0 so that we can configure the clock.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);

    //
    // Use the internal 16MHz oscillator as the UART clock source.
    //
    UARTClockSourceSet(UART0_BASE, UART_CLOCK_PIOSC);

    //
    // Select the alternate (UART) function for these pins.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Initialize the UART for console I/O.
    //
    UARTStdioConfig(0, 115200, 16000000);
}

//*****************************************************************************
//
// The interrupt handler for the for I2C0 data slave interrupt.
//
//*****************************************************************************
void
I2C0SlaveIntHandler(void)
{
    //
    // Clear the I2C0 interrupt flag.
    //
    I2CSlaveIntClear(I2C0_BASE);

    //
    // Read the data from the slave.
    //
    g_ui32DataRx = I2CSlaveDataGet(I2C0_BASE);

    //
    // Set a flag to indicate that the interrupt occurred.
    //
    g_bIntFlag = true;
}

//*****************************************************************************
//
// Configure the I2C0 master and slave and connect them using loopback mode.
//
//*****************************************************************************
int
main(void)
{
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    uint32_t ui32SysClock;
#endif
    uint32_t ui32DataTx;

    //
    // Set the clocking to run directly from the external crystal/oscillator.
    // TODO: The SYSCTL_XTAL_ value must be changed to match the value of the
    // crystal on your board.
    //
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ |
                                       SYSCTL_OSC_MAIN |
                                       SYSCTL_USE_PLL), 25000000);
#else
    SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                   SYSCTL_XTAL_16MHZ);
#endif

    //
    // The I2C0 peripheral must be enabled before use.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);

    //
    // For this example I2C0 is used with PortB[3:2].  The actual port and
    // pins used may be different on your part, consult the data sheet for
    // more information.  GPIO port B needs to be enabled so these pins can
    // be used.
    // TODO: change this to whichever GPIO port you are using.
    //
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

    //
    // Configure the pin muxing for I2C0 functions on port B2 and B3.
    // This step is not necessary if your part does not support pin muxing.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinConfigure(GPIO_PB2_I2C0SCL);
    GPIOPinConfigure(GPIO_PB3_I2C0SDA);

    //
    // Select the I2C function for these pins.  This function will also
    // configure the GPIO pins pins for I2C operation, setting them to
    // open-drain operation with weak pull-ups.  Consult the data sheet
    // to see which functions are allocated per pin.
    // TODO: change this to select the port/pin you are using.
    //
    GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);
    GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);

    //
    // Enable loopback mode.  Loopback mode is a built in feature that helps
    // for debug the I2Cx module.  It internally connects the I2C master and
    // slave terminals, which effectively lets you send data as a master and
    // receive data as a slave.  NOTE: For external I2C operation you will need
    // to use external pull-ups that are faster than the internal pull-ups.
    // Refer to the datasheet for more information.
    //
    HWREG(I2C0_BASE + I2C_O_MCR) |= 0x01;

    //
    // Enable the I2C0 interrupt on the processor (NVIC).
    //
    IntEnable(INT_I2C0);

    //
    // Configure and turn on the I2C0 slave interrupt.  The I2CSlaveIntEnableEx()
    // gives you the ability to only enable specific interrupts.  For this case
    // we are only interrupting when the slave device receives data.
    //
    I2CSlaveIntEnableEx(I2C0_BASE, I2C_SLAVE_INT_DATA);

    //
    // Enable and initialize the I2C0 master module.  Use the system clock for
    // the I2C0 module.  The last parameter sets the I2C data transfer rate.
    // If false the data rate is set to 100kbps and if true the data rate will
    // be set to 400kbps.  For this example we will use a data rate of 100kbps.
    //
#if defined(TARGET_IS_TM4C129_RA0) ||                                         \
    defined(TARGET_IS_TM4C129_RA1) ||                                         \
    defined(TARGET_IS_TM4C129_RA2)
    I2CMasterInitExpClk(I2C0_BASE, ui32SysClock, false);
#else
    I2CMasterInitExpClk(I2C0_BASE, SysCtlClockGet(), false);
#endif

    //
    // Enable the I2C0 slave module.
    //
    I2CSlaveEnable(I2C0_BASE);

    //
    // Set the slave address to SLAVE_ADDRESS.  In loopback mode, it's an
    // arbitrary 7-bit number (set in a macro above) that is sent to the
    // I2CMasterSlaveAddrSet function.
    //
    I2CSlaveInit(I2C0_BASE, SLAVE_ADDRESS);

    //
    // Tell the master module what address it will place on the bus when
    // communicating with the slave.  Set the address to SLAVE_ADDRESS
    // (as set in the slave module).  The receive parameter is set to false
    // which indicates the I2C Master is initiating a writes to the slave.  If
    // true, that would indicate that the I2C Master is initiating reads from
    // the slave.
    //
    I2CMasterSlaveAddrSet(I2C0_BASE, SLAVE_ADDRESS, false);

    //
    // Set up the serial console to use for displaying messages.  This is just
    // for this example program and is not needed for proper I2C operation.
    //
    InitConsole();

    //
    // Enable interrupts to the processor.
    //
    IntMasterEnable();

    //
    // Display the example setup on the console.
    //
    UARTprintf("I2C Slave Interrupt Example ->");
    UARTprintf("\n   Module = I2C0");
    UARTprintf("\n   Mode = Receive interrupt on the Slave module");
    UARTprintf("\n   Rate = 100kbps\n\n");

    //
    // Initialize the data to send.
    //
    ui32DataTx = 'I';

    //
    // Indicate the direction of the data.
    //
    UARTprintf("Transferring from: Master -> Slave\n");

    //
    // Display the data that I2C0 is transferring.
    //
    UARTprintf("  Sending: '%c'", ui32DataTx);

    //
    // Place the data to be sent in the data register.
    //
    I2CMasterDataPut(I2C0_BASE, ui32DataTx);

    //
    // Initiate send of single piece of data from the master.  Since the
    // loopback mode is enabled, the Master and Slave units are connected
    // allowing us to receive the same data that we sent out.
    //
    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_SEND);

    //
    // Wait for interrupt to occur.
    //
    while(!g_bIntFlag)
    {
    }

    //
    // Display that interrupt was received.
    //
    UARTprintf("\n  Slave Interrupt Received!\n");

    //
    // Display the data that the slave has received.
    //
    UARTprintf("  Received: '%c'\n\n", g_ui32DataRx);

    //
    // Loop forever.
    //
    while(1)
    {
    }
}

  • Double check that the stack value and the reset vector are programmed at locations 0x0000 and 0x0004. (Remember that the reset vector at address 0x0004 should be odd, it is one more than the address of the first instruction.)
    If that works, try the following:
    1. with the device already programmed, connect with CCS7 without "Loading" the code.
    2. Load the symbols by doing Run -> Load -> Load Symbols
    3. Reset the device with Run -> Reset -> System Reset
    4. Run the device (Run -> Resume)
    If the device fails to execute properly, you can debug it by repeating the procedure above but adding breakpoints before you run the code.

    One thing to look for is sections of code or initialized data that were linked into RAM instead of Flash, particularly if you had to make any modifications to the linker command file.
  • I was talking to Charles and he was able to recreate the problem. It appears that the first time you run the code it does not work, but the second time it does if you don't reset the peripherals. "Restart" re-runs the program without resetting the peripherals. I think some of the initialization is out of order. We are still working on it.
  • Glad to see that, "Exchange among pros" - unlikely for one person to, "know it all."
    Often my group has found such, "run only while debug pod attached" issues to be caused by an errant, misnamed or missing - "Start-Up file"...
  • Hi Schnitzel,

    Can you try to call the I2CSlaveEnable() before I2CSlaveIntEnableEx()? I find that with this sequence then it will work after you pull a system reset within CCS. The reason why the the program does not take the I2C slave interrupt is because the slave interrupt mask is not set to enable for interrupt. For some reason if the I2CSlaveIntEnableEx is called before I2CSlaveEnable then the interrupt mask is not set. I'm still doing some debugging because I still do not understand why it will work the first after you downloaded the code.
  • Hi Charles,

    Thank you very much Charls and Mr. Crosby for your quick reply and professional help. Indeed, the call of the I2CSlaveEnable() function before the I2CSlaveIntEnableEx() solved this problem. Now it works fine! Your solution description makes also sense.

    Best regards!
  • Hi Schnitzel,

    I just wanted to give some updates. The reason that it works the first time after your downloaded the code was because the ROM bootloader has already enabled I2C master and slave as part of the support for serial bootloading via UART, I2C, SSI and etc. You can check the I2CMCR and both the master and slave are enabled before I2CSlaveIntEnableEx() is called. When you reset the device the slave is first disabled. If you now call I2CSlaveIntEnableEx() before I2CSlaveEnable() then the write does not get through. This is also not well documented in the datasheet the relationship between writing to the I2CSIMR and the Slave enable bit.