fifo_cnt variable

[Sulymarco]

Hi everybody, I don't understand the use of the variable _fifocnt in the _ESC_readpram and _ESC_writepram functions: it is loaded, decrement and never used.

According to the LAN9252 datasheet we have to use it to see how many read/write we can perform without needing to check the status again, but this seems not to be the case in the code.

I know that the Microchip LAN9252 SSK code is exactly the same, but this doesn't confort me.

Am I missing something? Any comment is greatly appreciated.

Marco

[Sulymarco]

I am referring to the _eschw.c file for the LAN9252

Marco

[nakarlsson]

Seems wierd indeed, have you tried asking Microchip?

[Sulymarco]

No, not yet.

[Sulymarco]

I have submitted the issue to the Microchip support. I will update you about it.

In the meantime any comment is welcome.

Marco

[Sulymarco]

So far no answer from Microchip support :-( @nakarlsson (or @everybody else) please can also you submit the question to the Microchip support , just to give them a little bit pressure on the issue? It would be really interesting to have an answer from them !

Marco

[Sulymarco]

Finally I received an answer from Microchip (after more than one year)

Each FIFO will update at about 800nSec. So, we don’t need to poll the register every time since the PIC is running at a slower speed and polling will reduce the speed even further. If we add code to poll the available count, it will further decrease the throughput. If a high-performance MCU is used it is recommended to use a 1uSec delay or poll the available counter.

Marco

[nakarlsson]

Thanks , Ill close this