TMS320F2800157: Switching Master to Slave

With reference to this here is configuration

1st and 2nd board running same code base.

Both configured as Controller_Send_Mode, FIFO interrupt raised for 1 byte receive only, Both devices will its own address.

From 1st board the ISR for FIFO is called once which is received by the same ISR function on 2nd board, then in the same ISR code for sending back data is written, which should raise ISR in the first board for receiving.

pseudo code for ISR running on both boards

FIFO_ISR () {

//Code for receiving data will only be called in 2nd board if some data is received in RXFF buffer. In 1st board as this ISR is called manually this if clause will not run.

if ((I2C_getInterruptStatus(I2C_BASE) & I2C_INT_RXFF) != 0){
        rData =
                        I2C_getData(I2C_BASE);
    }

//Code for sending data which will run once this ISR function is called manually in 1st board and once in 2nd board when this ISR is raised due to receiving data  (RXFF)
    I2C_putData(
                        I2C_BASE,
                        sData;
    I2C_sendStartCondition(I2C_BASE);
    SysCtl_delay(50);
    I2C_sendStopCondition(I2C_BASE);
   
    I2C_clearInterruptStatus(I2C_BASE, I2C_INT_RXFF | I2C_INT_TXFF);
    Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP8);

}

In 1st board I was not getting ISR raised for getting received data from 2nd board.

But data transmission from 1st to 2nd is working fine.

Configuration done for both devices pseducode

I2C_disableModule(I2C_BASE);
    I2C_initController(I2C_BASE, DEVICE_SYSCLK_FREQ, 400000,
                       I2C_DUTYCYCLE_50);
    I2C_setConfig(I2C_BASE, I2C_CONTROLLER_SEND_MODE);
    I2C_setDataCount(I2C_BASE, 1);
    I2C_setBitCount(I2C_BASE, I2C_BITCOUNT_8);
    switch (some value)
    {
    case some value:
        I2C_setOwnAddress(I2C_BASE, 1st address);
        I2C_setTargetAddress(I2C_BASE, 2nd address);
        break;
    case some value:
        I2C_setOwnAddress(I2C_BASE, 2nd address);
        I2C_setTargetAddress(I2C_BASE, 1st address);
        break;
    }
    I2C_setEmulationMode(I2C_BASE, I2C_EMULATION_STOP_SCL_LOW);
    I2C_enableFIFO(I2C_BASE);
    I2C_setFIFOInterruptLevel(I2C_BASE, I2C_FIFO_TX1, I2C_FIFO_RX1);
    I2C_enableInterrupt(I2C_BASE, I2C_INT_RXFF | I2C_INT_STOP_CONDITION);
    I2C_clearInterruptStatus(I2C_BASE, I2C_INT_TXFF | I2C_INT_RXFF);
    I2C_disableLoopback(I2C_BASE);
    I2C_enableModule(I2C_BASE);

Hi Aishwarya,

I am trying the same using above code describe,

Can you please suggest me changes on my existing code for better understanding.

Regards,

Kaustuv

Inside the ISR itself after receiving how can I switch to the other mode for receiving. Should I use Controller or Target receiver. What else is needed to be done before switching? Please use the sample code above for explanation!

Regards,

Kaustuv

Kaustuv,

Have you looked at the table I referred to earlier (linked here)? Like I already mentioned, you cannot have two controllers in a system. There has to be a controller and a target. According to your code, you have two controllers sending data. Use i2c_ex3_external_loopback example as a reference as well.

Best Regards,

Aishwarya

Hi, Aishwarya

Thanks for the above document, earlier I was following some other document which was not enough.

From the new document I got to understand that if two TMS320F2800157 are connected with SDA, SCLK and if they want to communicate as master slave using FIFO register then the :-

1st Board - Controller Send Mode

2nd Board - Target Receiver Mode

Switch the configuration in runtime

1st Board - Controller Receive Mode

2nd Board - Target Send Mode

Note this system is not using any EEPROM.

If my understanding is correct considering the above configuration then can you provide me suitable example where 1 byte of data is transferred from Controller to Target and vice versa. The examples which comes with C2000 is not sufficient or not self explanatory and some examples confuses a lot.

Related to the above scenario and configuration can you kindly give another example of transferring only 1 byte of data from Transmitter (TMS320) to Controller (TMS320) board where Controller is initiated with Controller Receive Mode and Target in Target Send Mode. No data will be transferred from Controller to Target but Controller will always ask target to send data.

Regards

Kaustuv

Kaustuv,

Kaustuv Mandal said:

If my understanding is correct considering the above configuration then can you provide me suitable example where 1 byte of data is transferred from Controller to Target and vice versa. The examples which comes with C2000 is not sufficient or not self explanatory and some examples confuses a lot.

Related to the above scenario and configuration can you kindly give another example of transferring only 1 byte of data from Transmitter (TMS320) to Controller (TMS320) board where Controller is initiated with Controller Receive Mode and Target in Target Send Mode. No data will be transferred from Controller to Target but Controller will always ask target to send data.

Understanding is correct. Along with TRM documentation, refer to i2c_ex3_external_loopback.c and i2c_ex5_controller_target_interrupt as a basis for how to configure those requirements. We currently do not have examples that do exactly what you've described here. I've made a note of your request and feedback and will discuss with the team. If you have any specific questions regarding the examples or your test case, let me know.

Best Regards,

Aishwarya

Aishwarya,

Is it possible to start a controller as receiver and target as sender from initial stage and never switch to controller as sender and a target as receiver. From the flow chart given in the document shared I got to understand that it is possible to init the boards directly controller as receiver and a target as sender.

Is my understanding is correct then what steps I need follow to transmit data?

Hi Aishwarya,

What we discussed before is working absolutely fine. Now for our last step of the module development we need your suggestion.

Completed:

1. Configuring Master as Controller Receive Mode using FIFO

2. Configuring Slave as Target Send Mode using FIFO.

3. Provided some data (putData()) in Slave TX FIFO register.

3. Initialed Fetch Data through Master.

4. Received Data in Master RX FIFO from slave TX FIFO.

Last Step we need to complete:

1. As master is running asynchronously so it initiate call for transferring data non periodically.

2. On slave I need some mechanism like interrupts to intimidate that the TX FIFO register data of Slave is already transferred to Master and new data should be written on the same TX FIFO register so that next time or cycle master can get the new updated data.

Note: We are not changing any Configuration of Master using setConfig() between two consecutive Initiate calls for transferring data.  

We will be waiting for your suggestion!

Thanks

Regards,

Kaustuv