Home Forums Sparkfun MP3 Shield Library Support Forum Suggested refinements Reply To: Suggested refinements

#2659
Anonymous
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I don’t believe that there is a problem with the rate of transmission / ingestion. SPI sends the data in serial form. The rate at which the data is sent can be set up to a maximum rate defined by the hardware specification. That defined rate should be sufficient. If there was ever a concern otherwise then a lower clock rate should be set. After all, why only pause by checking for a response from the slave every 8 bits, we could have stomped on data before then.

Furthermore, there is already an inherent delay between sending bytes. The time taken to call the routine SPIClass::transfer(), the initial steps of that routine prior to sending data and the steps taken by the calling routine before every call already constitute an appreciable delay.

My view is that¬†SPIClass::transfer() has been written for generic devices. Some may respond after a byte has been sent with eg an error message, or the slave may send an unsolicited message and if it weren’t read quickly it could be lost. But with the VLSI chip there is a separate line used for handshaking (DREQ) and AFAIK, there are no unsolicited messages to expect.

So in the specific case of sending data to this VLSI chip I do not see a need to read after every byte has been sent, only to check DREQ after every 32 bits.