i.MX6SDL eSPI BIT_COUNT and BURST_LENGTH.

[satoshishimoda]

Hi community,

Our partner have a question about i.MX6S eCSPI BIT_COUND and BUSRT_LENGTH.

Please see the questions as below.

[Q1]

"BIT_COUNT" is mentioned in "21.7.3 Transmit Data Register (ECSPIx_TXDATA)" of reference manual (IMX6SDLRM Rev.1).

But, we can not find the bit field in "21.7.4 Control Register (ECSPIx_CONREG)" of reference manual.

I think "BIT_COUNT" is a misprint, "BURST_LENGTH" is correct, right?

[Q2]

Description of "BURST_LENGTH" is up to "2^7 words" written in "21.7.4 Control Register (ECSPIx_CONREG) Bit31:20" of reference manual.

We think this description shows "128 words", but we think there are only 64 words in FIFO.

Can you tell us relation of "BURST_LENGTH" and FIFO ?

Best Regards,

Satoshi Shimoda

[Yuri · Accepted solution]

Please look at my comments below.

1.

  Yes, it is assumed, that the BIT_COUNT is BURST_LENGTH.

2.
  FIFO size is less than the BURST_LENGTH : a transaction is not considered as
finished (SS is asserted) while all bits, defined via the field BURST_LENGTH, are
not transferred – with waiting (if needed) TXFIFO filling dynamically (during transfer).

Have a great day,
Yuri

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