I want to use the double data SPI mode to increase the speed of filling the SRAM. While it is clear to me, how to fill the RAM with two words written in parallel I'm not shure what to do with the intermediate register read/writes.
Do I need to disable the DOUBLESPI mode after each data block is written to the RAM before accessing any register?
I the DOUBLESPI mode can be active during register writes, what do I feed into the SPI2 pin during register read/writes? Accessing any register seems to be disallowed with this pin, according to the datasheet.
Last question, can I read the SRAM using both datalines? The datasheet is not clear: On page 18 (Double SPI Write for SRAM) it states: SDO/SDI2/ DOUT is write only in this mode; on page 28 (Register descriptions for SPI Control Register): This mode is available only for RAM data read or write.