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Difference between DTR mode and DTR protocol mode in OSPI controller

I see in OSPI controller registers, there two bits related to DDR modes. One is DDREN bit in OSPI_DRICTL register and other is DTREN in OSPI_CTL register. Which one should I be using to configure OSPI controller to work in DDR mode ?

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[edited by: JValeriani at 7:25 PM (GMT 0) on 3 Sep 2019]
  • When talking about the DDR mode, controller supports two variants of DDR mode of operation. One we call as DTR mode in which command is driven in SDR mode (on single edge of clock) and address/dummy cycles/data are driven in DDR mode (on both edges of clock). This is enabled when DDREN bit in OSPI_DRICTL register is set and DTREN bit in OSPI_CTL register is cleared.

    Other one is DTR protocol mode, where everything including command is driven in DDR mode. This requires the flash is already configured in a mode to accept the commands in DDR mode. Support for DTR protocol provides significant enhancement. This is enabled in the OSPI controller by setting DTREN bit in OSPI_CTL register. It improves performance further since the opcodes are also transmitted in DDR mode hence saving some additional cycles.