Fix SPI xfer logic to use correct edge and timing#5
Open
thekroko wants to merge 3 commits intocliffordwolf:masterfrom
Open
Fix SPI xfer logic to use correct edge and timing#5thekroko wants to merge 3 commits intocliffordwolf:masterfrom
thekroko wants to merge 3 commits intocliffordwolf:masterfrom
Conversation
This reads the SPI data while the clk is HIGH instead of low, and replaces the unecessary spin-loop with a single nop, resulting in a read frequency of ~1.4 MHz (measured via logic analyzer). Most SPI rams support reads up to at least 5 MHz. As a side effect, this significantly speeds up the flashing process, i.e. now it only takes 1.8s to flash the FPGA. This could be improved even more by getting rid of all the redundant spi_begin() and spi_end() calls, but at this point the flashing time is barely noticeable. pi@fpga:~/git/icotools/examples/icezero $ time ./icezprog ~/Downloads/default_te/python/gpio32_pwm6_te.bin Flash ID: EF 70 18 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Writing 0x000000 .. 0x00ffff: [erasing] [writing................] [readback................] Writing 0x010000 .. 0x01ffff: [erasing] [writing................] [readback................] Writing 0x020000 .. 0x02100a: [erasing] [writing..] [readback..] DONE. real 0m1.877s user 0m1.397s sys 0m0.261s
This way the FPGA can take over these lines, and start reading data from the SROM. Otherwise the reset might hang/fail.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This fixes issue #3, and speeds up the flashing process. I've tested this on a vanilla Raspberry Pi Zero W.
pi@fpga:~/git/icotools/examples/icezero $ time ./icezprog ~/Downloads/default_te/python/gpio32_pwm6_te.bin
Flash ID: EF 70 18 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Writing 0x000000 .. 0x00ffff: [erasing] [writing................] [readback................]
Writing 0x010000 .. 0x01ffff: [erasing] [writing................] [readback................]
Writing 0x020000 .. 0x02100a: [erasing] [writing..] [readback..]
DONE.