Does eTPU in MPC5777C has ROM memory to store microcode

[prathapvc]

Hi, I have the following queries to be clarified a) Does eTPU in MPC5777C has ROM memory that contains microcode with preprogrammed functions like similar to MC68332 Microcontroller which has TPU with ROM memory that contains factory preprogrammed functions with Mask Set G. b) Does any microcontroller in MPC57xx family has eTPU with ROM memory that contains microcode with preprogrammed functions? c) As understood by us from reference manual of MPC5777C, the eTPU includes 36KB code RAM and 9 KB parameter RAM only due to which the microcode has to be loaded into code RAM of eTPU everytime when we power on the MCU. This loading of microcode into code RAM of eTPU will affect the bootup time of our application so can you suggest any other solution to avoid loading of microcode into code RAM of eTPU everytime when we power on the MCU.

[davidtosenovjan]

Hi,

a) No, this concept has been abandoned with all versions of eTPU due to low flexibility. Only TPU modules (eTPU predecessors) used the code stored in ROM memory. eTPU always executes from RAM and so there is a need of copying the code from FLASH to RAM after every POR.

b) No, it does not.

c) No, there is not possible to avoid loading of the eTPU microcode. Note there is also initialization of internal SRAM taking certain portion of boot time.

You could play with performance optimization to speed it up the loading process.

It is needed to have configured clocks (PLL and so) and internal flash configuration (wait states) properly to speed it up loading process. Also you could load eTPU code by DMA or second core whilst main core may perform certain actions.

These all is application specific, dependent what is most time critical in your application, however initialization of internal RAMs after POR is necessary as well as loading of eTPU code from internal FLASH to eTPU code RAM.

[prathapvc]

Hi,

As you told loading of eTPU code can be done by second core whilst main core perform certain actions. Can you share any such example of executing different code in main core and second core.

Regards,

Prathap 

[davidtosenovjan]

Unfortunately we don't have such example but I have heard from certain customers, they use it this way. It is purely application specific, however code must be somehow loaded from internal FLASH to eTPU code RAM in order to be possible to start eTPU application.