SPI Support in TiMAC

Any thoughts on this topic?

Thank you,

     Craig Verrill

Hi Craig,

I'm not a big expert in TiMAC, however, I can suggest you a few things regarding SPI in CC2530.

I've implemented my own SPI module as an additional module of HAL in my projects,

though I did it in a complete version of TI's Zstack.

You can start by doing as I did. Write your own module for SPI (i.e. HAL_SPI.c and HAL_SPI.h)

and include this module in your project as a part of HAL.

(I'll be using the "msa_cc2530" project as an example):

The HAL_SPI.c module includes only two basic functions (as a first step): 

1. Some initialization function for configuring the SPI port and GPIOs, this depends whether the SPI configured
   as master or slave. The call for this function should be somewhere inside the MSA_Init( ) function in msa.c
2. Read/write function (readWriteSpi() ), which you can use for writing and reading data to/from SPI data
   buffer, that is the UxDBUF.

Writing your own SPI module:

1. A good place to start is by looking in DN113 document. If I remember this right, there is a mistake in
   SPI<->DMA configuration, however I don't remember what exactly is wrong. In case you'll decide that
   you want your SPI working with DMA, let me know, I'll look in my previous projects.
2. cc253x user's guide is also a good place to refer from time to time.

Carry out initialization, receive instructions from MSP430 over SPI, etc.:

1. First of all you should decide who is the master and who is the slave in your MSP430<->CC2530 system.
2. In case the cc2530 configured as master you can simply call to readWriteSpi( ) any time you got some
   information for the MSP430. The data from the MSP can be parsed and handled as a state machine,
   invoking transfer of data to the cc2530's radio and eventually to ZigBee network (just an example).
   OSAL API can be very helpful with timing and scheduling.
3. The communication between those two devices through the SPI can be implemented by your own protocol
   (lets say, OPCODE driven).
4. I've no good example in case the cc2530 acts like a slave, but i'm sure you can figure something out.

Maybe there is a better and easier way to implement these functionalities, so please wait for an answer from TI experts before you take my suggestions.

Anyway, I hope this helps.

Br,

Igor.

Hi Igor,

     Thanks for the suggestions. I have decided to implement SPI using the CC2530 as the master device and the MSP430 as the slave device. I have written the initialization function and ReadWriteSPI() based on the example in DN113.

// Method 1; SSN kept low during the transfer of all bytes

int* ReadWriteSPI(int length, int* txBufferMaster)

{

            int i;

SSN = LOW;

for (i = 0; i <= length; i++)

{

U1DBUF = txBufferMaster[i];

while (!(U1CSR && U1TX_BYTE));

U1DBUF = rxBufferMaster[i];

}

SSN = HIGH;

return rxBufferMaster;

}

I have also implemented a look-up table using OPCODEs to translate bytes passed over SPI to TiMAC function calls. It seems that I am very close on this project, but I am still confused in one area. TiMAC, like Z-stack is mostly task based. I don't know where or how to add the ReadWriteSPI task to the event queue. I have followed the program flow of TiMAC, and after all initializations are carried out, osal_start_system() is called, and the program goes into an infinite loop checking and handling tasks. I have attached a document describing what I believe to be the main program flow of TiMAC. If you could help me understand where and how to place an event into the event queue, I would be delighted and extremely grateful. (It looks to have something to do with the function HalSpiPoll() in Hal_ProcessPoll(), but this is a precompiled external function that is not available for me to see in the TiMAC source)

8080.TIMAC program flow.pdf

Thanks again,

     Craig Verrill

Thanks Igor,

     This information was a major help. Much appreciated.

Craig Verrill