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spi_flash: document register fields 

Document the various fields present in the SPI flash bitbang interface.
This adds documentation for the Single and DualQuad modules.

Signed-off-by: Sean Cross <sean@xobs.io>
This commit is contained in:
Sean Cross 2019-09-20 12:11:59 +08:00
parent 4f659ba422
commit 1a6dddd57c
1 changed files with 20 additions and 6 deletions
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26
litex/soc/cores/spi_flash.py
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@ -87,9 +87,18 @@ class SpiFlashDualQuad(SpiFlashCommon, AutoCSR):
assert spi_width >= 2
if with_bitbang:
self.bitbang = CSRStorage(4)
self.miso = CSRStatus()
self.bitbang_en = CSRStorage()
self.bitbang = CSRStorage(4, fields=[
CSRField("mosi", description="MOSI output pin, valid whenever `dir` is `0`."),
CSRField("clk", description="Output value for SPI CLK line."),
CSRField("cs_n", description="Output value of SPI CSn line."),
CSRField("dir", description="Dual/Quad SPI reuses pins SPI pin direction.", values=[
("0", "OUT", "SPI pins are all output"),
("1", "IN", "SPI pins are all input"),
])
], description="""Bitbang controls for SPI output. Only standard 1x SPI is supported,
meaning the IO2 and IO3 lines will be hardwired to `1` during bitbang mode.""")
self.miso = CSRStatus(description="Incoming value of MISO signal.")
self.bitbang_en = CSRStorage(description="Write a `1` here to disable memory-mapped mode and enable bitbang mode.")
# # #
@ -212,9 +221,14 @@ class SpiFlashSingle(SpiFlashCommon, AutoCSR):
self.bus = bus = wishbone.Interface()
if with_bitbang:
self.bitbang = CSRStorage(4)
self.miso = CSRStatus()
self.bitbang_en = CSRStorage()
self.bitbang = CSRStorage(4, fields=[
CSRField("mosi", description="MOSI output pin. Always valid in this design."),
CSRField("clk", description="Output value for SPI CLK line."),
CSRField("cs_n", description="Output value of SPI CSn line."),
CSRField("dir", description="Unused in this design.")
], description="""Bitbang controls for SPI output.""")
self.miso = CSRStatus(description="Incoming value of MISO signal.")
self.bitbang_en = CSRStorage(description="Write a `1` here to disable memory-mapped mode and enable bitbang mode.")
# # #