TMS320F28384S: Passing NULL reference from C28 to CM

Carlo,

You are trying to typecast NULL to unsigned integer. You cannot do that. NULL is usually assigned to pointers. Why can't you directly send the actual unsigned integer value.

Regards,

Manoj

Hello Manoj,

thank you for response. I am sorry to answer only now, but I was out of office for some days.

I'm not sure that I have understood your answer.

As shown on TI examples, data struct addresses are passed as pointes type casted to uint32_t, as shown in the following code snippet taken from ipc_ex1_basic_c28x1 example.

#pragma DATA_SECTION(readData, "MSGRAM_CPU_TO_CM")
uint32_t readData[10];

IPC_sendCommand(IPC_CPU1_L_CM_R, IPC_FLAG0, IPC_ADDR_CORRECTION_ENABLE,
IPC_CMD_READ_MEM, (uint32_t)readData, 10);

In this way, to get my code compact and clean I used this pattern also with NULL, in the case I don't have any data struct to pass from C28 to CM.

As already said, NULL (that is defined as 0 in string.h) is transformed in 0xA000E000 on CM side, and I wonder why.

Thank you,

Carlo.

Carlo,

Carlo Taboni33 said:

IPC_sendCommand(IPC_CPU1_L_CM_R, IPC_FLAG0, IPC_ADDR_CORRECTION_ENABLE,
IPC_CMD_READ_MEM, (uint32_t)readData, 10);

Did you try single stepping through the code and check from C28x side what is getting written from C28x side? I'm currently sick and would take couple of days to recover. I can try this when I get back in office on friday.

Regards,

Manoj

Hello Manoj,
I hope you are feeling better.

I tried to step into IPC_sendCommand() but I had some sort symbols disaligment problems, and I wasn't able to get a lot.
The only think I have seen, is that if IPC_ADDR_CORRECTION_ENABLED flag is set, the following adjustment is performed:

IPC_Instance[ipcType].IPC_SendCmd_Reg->IPC_SENDADDR = addr - IPC_Instance[ipcType].IPC_MsgRam_LtoR; 

Thank you,
Carlo

Does the problem go away when you enable address correction? Address correction needs to be enabled for M4 - C28x (or) C28x - M4 because C28x 's word size if 16 bits and M4 word size is 8 bit.

Regards,

Manoj

Hello Manoj,
I am already using IPC_ADDR_CORRECTION_ENABLE flag.

On C28 side, I call:

IPC_sendCommand(
    IPC_CPU1_L_CM_R,
    MY_IPC_FLAG,
    IPC_ADDR_CORRECTION_ENABLE,
    myInfo,
    (uint32_t) NULL,
    0);

On CM side I call:

if (IPC_readCommand(
    IPC_CM_L_CPU1_R,
    MY_IPC_FLAG,
    IPC_ADDR_CORRECTION_ENABLE,
    &myInfo,
    &addr,
    &unused))

and 'addr' is equal to 0xA000E000.

Regards,
Carlo

Okay. I need to check this myself and get back with you. Please give me 3 - 4 business days to get back with you.

Regards,

Manoj