TMS320F28384S: The address data error of CM4 function pointer.

Luke Chen

Hi champs,

My customer uses one array to save function pointer(address) and faces a strange problem.

From below screenshot, you can see the address of function RS485_UART_voSetMdbusPktFmt() is 0x00219A90, but the address data value is 0x00219A91 when he saves the function address into array.

This problem happened when he is doing CM4 coding, but the code works well in c28x.

Please advise how to solve this problem, thanks for help.

Regards,

-Luke

over 4 years ago

0 MatthewPate over 4 years ago

TI__Guru* 85910 points

Luke,

We are working to get this correctly assigned to a C2000 engineer. Appreciate your patience.

Best,

Matthew

0 JohnS over 4 years ago in reply to MatthewPate

TI__Guru**** 163185 points

Luke,

Our compiler expert is out until Monday and will take a look when he returns.

Regards,

John

+1 Chester Gillon over 4 years ago

Guru 92251 points

Luke Chen said:
From below screenshot, you can see the address of function RS485_UART_voSetMdbusPktFmt() is 0x00219A90, but the address data value is 0x00219A91 when he saves the function address into array.

The Arm Cortex-M4 used as the Connectivity Manager (CM) in theTMS320F28384S only supports THUMB mode.

As explained by Pointers to functions in Thumb state it is the correct behaviour for pointers to functions in THUMB mode to have the least significant bit set.

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TMS320F28384S: The address data error of CM4 function pointer.