To read data from the external flash do we send dummy data, In QSPI protocol

[chethan sk]

Posted on July 01, 2018 at 15:53

hello, 

i am using STM32L432KC MCU to read data from the external flash through QSPI protocol. 

I am setting Instruction, Address , dummy cycle and Data phase and activating indirect read mode.

But i have a doubt that are we sending dummy data to external flash to receive data from the external flash.

[Tesla DeLorean]

Posted on July 01, 2018 at 16:52

In SPI you send dummy data to clock the interface, the QSPI isn't typically doing that, you're clocking it and getting 4-bits back in every cycle, the bus isn't changing direction.

If you have doubts, look at the data sheet for the QSPI memory you are using, and the commands you are sending. If you need more validation, use a logic analyzer and observe directly.

[chethan sk]

Posted on July 01, 2018 at 20:36

thank you for the information clive

[chethan sk]

Posted on July 02, 2018 at 06:30

Then how master is generating clock in data phase for slave without sending dummy data