Run from SPI FLASH does not work

BrunoLevy / learn-fpga

Learning FPGA, yosys, nextpnr, and RISC-V

BSD 3-Clause "New" or "Revised" License

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Run from SPI FLASH does not work #19

Closed BrunoLevy closed 3 years ago

BrunoLevy commented 3 years ago

@mecrisp experienced problems with the run from SPI flash mode.

BrunoLevy commented 3 years ago

Created example programs Mandelbrot on the OLED screen works What does not work: LOAD from mapped SPI-flash data Don't know why: test_spi_fash.c works when executed from BRAM ... still investigating...

BrunoLevy commented 3 years ago

Was due to too short delay between fetch data and fetch instr through SPI. Added another wait cycle to the busy signal.
Directly start with PC in SPI does not work (opened another issue)