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Diffstat (limited to 'doc/SPI/README.dual-flash')
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diff --git a/doc/SPI/README.dual-flash b/doc/SPI/README.dual-flash deleted file mode 100644 index 6c88d65..0000000 --- a/doc/SPI/README.dual-flash +++ /dev/null @@ -1,92 +0,0 @@ -SPI/QSPI Dual flash connection modes: -===================================== - -This describes how SPI/QSPI flash memories are connected to a given -controller in a single chip select line. - -Current spi_flash framework supports, single flash memory connected -to a given controller with single chip select line, but there are some -hw logics(ex: xilinx zynq qspi) that describes two/dual memories are -connected with a single chip select line from a controller. - -"dual_flash" from include/spi.h describes these types of connection mode - -Possible connections: --------------------- -SF_SINGLE_FLASH: - - single spi flash memory connected with single chip select line. - - +------------+ CS +---------------+ - | |----------------------->| | - | Controller | I0[3:0] | Flash memory | - | SPI/QSPI |<======================>| (SPI/QSPI) | - | | CLK | | - | |----------------------->| | - +------------+ +---------------+ - -SF_DUAL_STACKED_FLASH: - - dual spi/qspi flash memories are connected with a single chipselect - line and these two memories are operating stacked fasion with shared buses. - - xilinx zynq qspi controller has implemented this feature [1] - - +------------+ CS +---------------+ - | |---------------------->| | - | | I0[3:0] | Upper Flash | - | | +=========>| memory | - | | | CLK | (SPI/QSPI) | - | | | +---->| | - | Controller | CS | | +---------------+ - | SPI/QSPI |------------|----|---->| | - | | I0[3:0] | | | Lower Flash | - | |<===========+====|====>| memory | - | | CLK | | (SPI/QSPI) | - | |-----------------+---->| | - +------------+ +---------------+ - - - two memory flash devices should has same hw part attributes (like size, - vendor..etc) - - Configurations: - on LQSPI_CFG register, Enable TWO_MEM[BIT:30] on LQSPI_CFG - Enable U_PAGE[BIT:28] if U_PAGE flag set - upper memory - Disable U_PAGE[BIT:28] if U_PAGE flag unset - lower memory - - Operation: - accessing memories serially like one after another. - by default, if U_PAGE is unset lower memory should accessible, - once user wants to access upper memory need to set U_PAGE. - -SPI_FLASH_CONN_DUALPARALLEL: - - dual spi/qspi flash memories are connected with a single chipselect - line and these two memories are operating parallel with separate buses. - - xilinx zynq qspi controller has implemented this feature [1] - - +-------------+ CS +---------------+ - | |---------------------->| | - | | I0[3:0] | Upper Flash | - | |<=====================>| memory | - | | CLK | (SPI/QSPI) | - | |---------------------->| | - | Controller | CS +---------------+ - | SPI/QSPI |---------------------->| | - | | I0[3:0] | Lower Flash | - | |<=====================>| memory | - | | CLK | (SPI/QSPI) | - | |---------------------->| | - +-------------+ +---------------+ - - - two memory flash devices should has same hw part attributes (like size, - vendor..etc) - - Configurations: - Need to enable SEP_BUS[BIT:29],TWO_MEM[BIT:30] on LQSPI_CFG register. - - Operation: - Even bits, i.e. bit 0, 2, 4 ., of a data word is located in the lower memory - and odd bits, i.e. bit 1, 3, 5, ., of a data word is located in the upper memory. - -Note: Technically there is only one CS line from the controller, but -zynq qspi controller has an internal hw logic to enable additional CS -when controller is configured for dual memories. - -[1] http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf - --- -Jagannadha Sutradharudu Teki <jaganna@xilinx.com> -05-01-2014. |