prog rom generation using Amaranth

1 files changed, 81 insertions, 0 deletions

diff --git a/hdl/rom.py b/hdl/rom.py
new file mode 100644
index 0000000..d370e7d
--- /dev/null
+++ b/hdl/rom.py
@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+"""
+Convert an Intel HEX file to a Verilog ROM module using Amaranth.
+Usage:
+  python3 hex2rom_amaranth.py program.hex > prog_rom.v
+Produces a module 'prog_rom' with:
+  input clk, input [12:0] addr, output [13:0] data
+Depth defaults to 4096 (8192/2).
+"""
+import sys
+import argparse
+from amaranth import *
+from amaranth.back import verilog
+
+DEPTH = 8192 // 2
+DATA_WIDTH = 14
+ADDR_WIDTH = 13  # external addr width
+
+def parse_ihex(path):
+    words = [0] * DEPTH
+    with open(path) as f:
+        for line in f:
+            line = line.strip()
+            if not line.startswith(':'):
+                continue
+            byte_count  = int(line[1:3],   16)
+            address     = int(line[3:7],   16)
+            record_type = int(line[7:9],   16)
+            if record_type != 0:
+                continue
+            data = bytes.fromhex(line[9:9 + byte_count * 2])
+            for i in range(0, len(data) - 1, 2):
+                word_addr = (address + i) // 2
+                if 0 <= word_addr < DEPTH:
+                    words[word_addr] = (data[i] | (data[i+1] << 8)) & ((1 << DATA_WIDTH) - 1)
+    return words
+
+def make_rom_module(words):
+    m = Module()
+
+    clk  = Signal()
+    addr = Signal(ADDR_WIDTH)
+    data = Signal(DATA_WIDTH)
+
+    mem = Memory(width=DATA_WIDTH, depth=DEPTH, init=words)
+    rd  = mem.read_port(transparent=False)
+    m.submodules += rd
+
+    m.d.comb += [
+        rd.addr.eq(addr),
+        data.eq(rd.data)
+    ]
+
+    return m, clk, addr, data
+
+def render_verilog(words, module_name="prog_rom"):
+    m, clk, addr, data = make_rom_module(words)
+    v = verilog.convert(m, ports=[clk, addr, data], name=module_name)
+    return v.replace("(* top =  1  *)\n", "(* top = 0  *)\n")
+
+class ComponentWrapper(Elaboratable):
+    def __init__(self, module_obj, ports, name="prog_rom"):
+        self._module = module_obj
+        self._ports = ports
+        self._name = name
+
+    def elaborate(self, platform=None):
+        return self._module
+
+    def name(self):
+        return self._name
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument('hexfile')
+    parser.add_argument('--module-name', default='prog_rom')
+    args = parser.parse_args()
+
+    words = parse_ihex(args.hexfile)
+    v = render_verilog(words, module_name=args.module_name)
+    sys.stdout.write(v)