suggestion on how to implement duel /quad spi interface

[longpole001]

did not know that shiftin out did more than 8 bit at a time , nice to know ,

i ll take a look at the how it may be done with the MSSP , be nice feature to have running when i get the flash chips that have the duel/ quad interface .
project on hand does not need it but future ones will

the example code i have on hand that uses the MSSP is as follows , suggestions on how this maybe changed

 
' --- Hardware SPI / SSP register variables ---------------------------
   SSPEN	Var	SSPCON1.5	' SSP enable
    WCOL	Var	SSPCON1.7	' SSP write collision
    BF		Var	SSPSTAT.0	' SSP buffer full
    SSPIF	Var	PIR1.3		' SSP interrupt flag


SPI_init:

	        SSPSTAT = %00000000	    ' Sample at middle of data output time, Mode 1, 1: Transmit on idle to active clock transition.
		SSPCON1 = %00010000	    ' SPI master mode, clock = Fosc/64, Mode 1, 1: Clock idle high.
		SSPEN = 1		            ' Enable hardware SPI port.

return



Readbyte:
	       SDC_data_in = SSPBUF	            ' Clear the buffer.
		SSPIF = 0		                    ' Clear the interrupt flag.
		SSPBUF = $ff		                ' Shift out a dummy byte.
		While !SSPIF		                ' Wait for receive byte.
		Wend
		SDC_data_in = SSPBUF	            ' Get the byte.

return

writebyte:

	        SDC_data_in = SSPBUF	        ' Clear the buffer.
		SSPIF = 0	         	        ' Clear the interrupt flag.
		SSPBUF = SDC_data_out	' Send the byte.
		If (WCOL) Then Return	        ' Check for write collision.
		While !SSPIF		        ' Wait for send to complete.
		Wend
return

[HenrikOlsson]

Hi Sheldon,
I'm not sure but I think there might be some confusion going on here.
Neither SHIFTIN/SHIFTOUT nor the MSSP module will be able to handle dual or quad SPI interface - period.
If you're going to do it you'll have to bitbang it yourself which, again, is probably slower than doing it "normaly" with the MSSP module.

The thing with dual and quad SPI is that it's getting closer to a parallell bus. With dual SPI there are two datalines and with quad SPI there are four (instead of one) that get sampled on the active edge of the clock. SHIFTIN/SHIFTOUT doesn't support it and the MSSP module only have one data line input so it's impossible.

/Henrik.