Problems getting Master Transfer Block to function

I would welcome a pointer to some clearer documentation for the c28x SPI Master Transfer block in provided for TI MCU for use in Simulink.

The description implies that after a WREN has been transmitted, an opcode byte of WRITE can then be followed by a 3 byte address and then as much data as is to be written. The data in bytes, but communicated as an array of 16 bit blocks in Simulink.

The documentation states "

Register address — SPI register address

0 (default) | positive integer scalar | positive integer vector

The slave register address from which the block reads data.

Note

The positive integer vector is specified as, [2 0 32] for Write Data to Memory and [3 0 32] for Read Data from Memory. For more information, refer to the example Using SPI to Read and Write Data to SPI EEPROM.

"

I can deduce that the "2" equates to the WRITE command, but as to the 0 and 32 there is no extra information given in the example mentioned.

The fairly trivial task is to write a variable "n" bytes to an chosen address "x" on an NVRAM chip and then read "n" bytes back at a later stage, but hooking up the block in Simulink is not proving simple.

I have tried to set up the read, but get complation errors, unless I place a selector block in the path to strip out the initial data bytes (It isn't clear whether the "read command and address bytes" are part of the returned stream.

I asked this first on the TI forum, and the response was to contact Mathworks.

Answer 1

[Ayush Gupta]

Hi @Graham Cotgreave,

Here the address is split as 0x00 (0) and 0x20 (32) as two 8-bit numbers and is entered in the register address. The reason for splitting it as two 8-bit numbers is the setting in Data bits parameter in Advanced tab. Since this is set to 8 bits, the data in the vector format should not be considered more than 8-bit. If you select the parameter as 16, then 0 and 32 corresponds to 32-bit address (0x00000020) instead of 16-bit.

To read more about it kinldy see the following documentation: https://www.mathworks.com/help/ti-c2000/ref/c28xspicontrollertransfer.html#:~:text=Here%20the%20address,of%2016%2Dbit.

Hope it helps!

Thank you,

Ayush Gupta