Added Uart.

exi_bba/synth.py

@@ -68,12 +68,21 @@ class IceBreakerPlatform(LatticeICE40Platform):
         # Bring-up status panel → iCEbreaker ONBOARD parts (dedicated pins, not
         # on any PMOD, so they coexist with EXI + W5100).  LEDR/LEDG are
         # active-low discrete LEDs; BTN_N is the user button.
-        # (The onboard RGB LED on pins 39/40/41 needs an SB_RGBA_DRV instance
-        # wired to raw pads — board/version-specific — left as a future add-on
-        # to expose rx/tx/ready as colours; the 2 discrete LEDs cover bring-up.)
+        # RGB LED (pins 39/40/41) is driven via SB_RGBA_DRV — not declared here
+        # as a platform resource (see BBATopSynth.elaborate, status_panel block).
         Resource("ledr", 0, Pins("11", dir="o"), Attrs(IO_STANDARD="SB_LVCMOS")),
         Resource("ledg", 0, Pins("37", dir="o"), Attrs(IO_STANDARD="SB_LVCMOS")),
         Resource("btn",  0, Pins("10", dir="i"), Attrs(IO_STANDARD="SB_LVCMOS")),
+
+        # UART debug console → iCEbreaker FT2232H Channel B (onboard USB-UART).
+        # No external hardware needed — the FT2232H is already on the board.
+        # On the PC: open the second USB serial port at 115200 8N1.
+        #   pin  9 = FPGA TX → FT2232H Channel B RX  (FPGA drives)
+        #   pin  6 = FPGA RX ← FT2232H Channel B TX  (FPGA reads)
+        Resource("uart", 0,
+                 Subsignal("tx", Pins("9",  dir="o")),
+                 Subsignal("rx", Pins("6",  dir="i")),
+                 Attrs(IO_STANDARD="SB_LVCMOS")),
     ]
 
     connectors = []
@@ -153,6 +162,14 @@ class BBATopSynth(BBATop):
                     o_RGB2=Signal(name="rgb_b"),
                 )
 
+            # ── UART debug console → FT2232H Channel B ─────────────────────
+            if self._uart_console:
+                uart = platform.request("uart", 0)
+                m.d.comb += [
+                    uart.tx.o       .eq(self.uart_tx),
+                    self.uart_rx    .eq(uart.rx.i),
+                ]
+
         return m
 
 
@@ -181,7 +198,7 @@ if __name__ == "__main__":
         print(f"{'='*60}")
         opts = (f"--opt-timing --seed {seed} --timing-allow-fail")
         try:
-            platform.build(BBATopSynth(status_panel=True), do_program=False,
+            platform.build(BBATopSynth(status_panel=True, uart_console=True), do_program=False,
                            verbose=True, nextpnr_opts=opts)
         except Exception as exc:
             # nextpnr exits non-zero even with --timing-allow-fail on some
@@ -212,7 +229,7 @@ if __name__ == "__main__":
     if do_flash:
         print(f"\nFlashing with seed {best_seed}...")
         opts = f"--opt-timing --seed {best_seed} --timing-allow-fail"
-        platform.build(BBATopSynth(status_panel=True), do_program=True,
+        platform.build(BBATopSynth(status_panel=True, uart_console=True), do_program=True,
                        verbose=True, nextpnr_opts=opts)
 
     print("Done.")