microwatt

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History

Anton Blanchard db937403ec Initial support for ghdl synthesis A first pass at ghdl synthesis using yosys and nextpnr. It runs hello world or micropython if the FPGA has enough block RAM (eg ECP5 85F). The hello world testcase also loops UART rx to tx in software (ie not a hardware loopback). It uses Docker images, so no software needs to be installed. If you prefer podman you can use that too. Edit Makefile.synth to configure your FPGA, JTAG device etc. To build: make -f Makefile.synth and to program: make -f Makefile.synth prog A few issues: We need to add PLL support. Right now Microwatt runs at whatever the external clock frequency is and the baud rate gets scaled by how far off 50MHz it is. This means on the ecp5-evn with a 12 MHz clock rate the baud rate is a quite strange 27650 (115200 * 50 / 12). On my OrangeCrab with a 50MHz clock the UART is 115200. It uses a large amount of resources, way more than it should. There are still some ghdl/yosys issues to be sorted out. Signed-off-by: Anton Blanchard <anton@linux.ibm.com>	5 years ago
..
ecp5-evn.lpf	Initial support for ghdl synthesis	5 years ago
orange-crab.lpf	Initial support for ghdl synthesis	5 years ago

Anton Blanchard db937403ec Initial support for ghdl synthesis

A first pass at ghdl synthesis using yosys and nextpnr. It runs hello world
or micropython if the FPGA has enough block RAM (eg ECP5 85F). The hello
world testcase also loops UART rx to tx in software (ie not a hardware
loopback).

It uses Docker images, so no software needs to be installed. If you prefer
podman you can use that too. Edit Makefile.synth to configure your FPGA,
JTAG device etc.

To build:

make -f Makefile.synth

and to program:

make -f Makefile.synth prog

A few issues:

We need to add PLL support. Right now Microwatt runs at whatever the
external clock frequency is and the baud rate gets scaled by how far off
50MHz it is. This means on the ecp5-evn with a 12 MHz clock rate the baud
rate is a quite strange 27650 (115200 * 50 / 12). On my OrangeCrab with a
50MHz clock the UART is 115200.

It uses a large amount of resources, way more than it should. There are
still some ghdl/yosys issues to be sorted out.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>

ecp5-evn.lpf

Initial support for ghdl synthesis

orange-crab.lpf

Initial support for ghdl synthesis