fpga: allow selecting the Humpback EEM port

README.md

@@ -14,7 +14,7 @@ Once you have Flakes enabled, you can use ``nix build`` to build the firmware.
 Alternatively, you can develop and build it within Nix shell:
 ```shell
 nix develop
-python fpga/fpga_config.py
+python fpga/fpga_config.py [--eem [0,1,2]]
 cargo build --release
 ```
 

fpga/fpga_config.py

@@ -1,3 +1,5 @@
+import argparse
+
 # Import built in I/O, Connectors & Platform template for Humpback
 from migen.build.platforms.sinara import humpback
 # Import migen pin record structure
@@ -8,7 +10,7 @@ from migen.genlib.io import *
 
 
 class UrukulConnector(Module):
-    def __init__(self, platform):
+    def __init__(self, platform, eem_resource_name):
         # Include extension
         spi_mosi = [
             ("spi_mosi", 0, Pins("B16"), IOStandard("LVCMOS33"))
@@ -26,16 +28,16 @@ class UrukulConnector(Module):
         platform.add_extension(spi_mosi)
 
         # Request EEM I/O & SPI
-        eem0 = [
+        eem = [
-            platform.request("eem0", 0),
+            platform.request(eem_resource_name, 0),
-            platform.request("eem0", 1),
+            platform.request(eem_resource_name, 1),
             # Supply EEM pin with negative polarity
             # See issue/PR: https://github.com/m-labs/migen/pull/181
-            platform.request("eem0_n", 2),
+            platform.request(f"{eem_resource_name}_n", 2),
-            platform.request("eem0", 3),
+            platform.request(eem_resource_name, 3),
-            platform.request("eem0", 4),
+            platform.request(eem_resource_name, 4),
-            platform.request("eem0", 5),
+            platform.request(eem_resource_name, 5),
-            platform.request("eem0", 6)
+            platform.request(eem_resource_name, 6)
         ]
         spi = platform.request("spi")
         spi_mosi = platform.request("spi_mosi")
@@ -56,37 +58,47 @@ class UrukulConnector(Module):
         self.specials += Instance("SB_IO",
                             p_PIN_TYPE=C(0b000001, 6),
                             p_IO_STANDARD="SB_LVDS_INPUT",
-                            io_PACKAGE_PIN=eem0[2],
+                            io_PACKAGE_PIN=eem[2],
                             o_D_IN_0=self.miso_n
                         )
 
         # Link EEM to SPI
         self.comb += [
 
-            eem0[0].p.eq(spi.clk),
+            eem[0].p.eq(spi.clk),
-            eem0[0].n.eq(~spi.clk),
+            eem[0].n.eq(~spi.clk),
 
-            eem0[1].p.eq(spi_mosi),
+            eem[1].p.eq(spi_mosi),
-            eem0[1].n.eq(~spi_mosi),
+            eem[1].n.eq(~spi_mosi),
 
             spi.miso.eq(~self.miso_n),
 
-            eem0[3].p.eq(spi_cs[0]),
+            eem[3].p.eq(spi_cs[0]),
-            eem0[3].n.eq(~spi_cs[0]),
+            eem[3].n.eq(~spi_cs[0]),
 
-            eem0[4].p.eq(spi_cs[1]),
+            eem[4].p.eq(spi_cs[1]),
-            eem0[4].n.eq(~spi_cs[1]),
+            eem[4].n.eq(~spi_cs[1]),
 
-            eem0[5].p.eq(spi_cs[2]),
+            eem[5].p.eq(spi_cs[2]),
-            eem0[5].n.eq(~spi_cs[2]),
+            eem[5].n.eq(~spi_cs[2]),
 
-            eem0[6].p.eq(io_update),
+            eem[6].p.eq(io_update),
-            eem0[6].n.eq(~io_update),
+            eem[6].n.eq(~io_update),
 
             led.eq(1)
         ]
 
 
 if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Build FPGA bitstream")
+    parser.add_argument(
+        "--eem",
+        type=int,
+        choices=[0, 1, 2],
+        default=0,
+        help="The Humpback EEM port the Urukul board is connected to."
+    )
+    args = parser.parse_args()
+
     platform = humpback.Platform()
-    platform.build(UrukulConnector(platform))
+    platform.build(UrukulConnector(platform, f"eem{args.eem}"))