From 8a9fd02768dff6c6dbd699662f2d8d52cecc7953 Mon Sep 17 00:00:00 2001
From: David Shah <dave@ds0.me>
Date: Sat, 5 Sep 2020 09:58:28 +0100
Subject: [PATCH] crosslink_nx_evn: Improve documentation on UART jumpers

Signed-off-by: David Shah <dave@ds0.me>
---
 litex_boards/platforms/crosslink_nx_evn.py | 3 ++-
 litex_boards/targets/crosslink_nx_evn.py   | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/litex_boards/platforms/crosslink_nx_evn.py b/litex_boards/platforms/crosslink_nx_evn.py
index 099a060..e0440e8 100644
--- a/litex_boards/platforms/crosslink_nx_evn.py
+++ b/litex_boards/platforms/crosslink_nx_evn.py
@@ -25,7 +25,8 @@ _io = [
     ("user_btn", 1, Pins("G15"), IOStandard("LVCMOS33")),  # SW3
 
     # Section 6.2 UART Topology
-    # Requires installation of 0-ohm jumpers to properly route signals
+    # Requires installation of 0-ohm jumpers R15 and R17 to properly route signals
+    # Note that it is R15 and R17, not R16 and R17 as stated in the user guide
     ("serial", 0,
         Subsignal("rx", Pins("F16"), IOStandard("LVCMOS33")),
         Subsignal("tx", Pins("F18"), IOStandard("LVCMOS33")),
diff --git a/litex_boards/targets/crosslink_nx_evn.py b/litex_boards/targets/crosslink_nx_evn.py
index 6158512..f01911c 100755
--- a/litex_boards/targets/crosslink_nx_evn.py
+++ b/litex_boards/targets/crosslink_nx_evn.py
@@ -99,7 +99,7 @@ def main():
     parser.add_argument("--build", action="store_true", help="Build bitstream")
     parser.add_argument("--load", action="store_true", help="Load bitstream")
     parser.add_argument("--sys-clk-freq",  default=75e6, help="System clock frequency (default=75MHz)")
-    parser.add_argument("--serial",  default="serial", help="UART Pins: serial or serial_pmod[0-2] (default=serial)")
+    parser.add_argument("--serial",  default="serial", help="UART Pins: serial (requires R15 and R17 to be soldered) or serial_pmod[0-2] (default=serial)")
     parser.add_argument("--prog-target",  default="direct", help="Programming Target: direct or flash")
     builder_args(parser)
     soc_core_args(parser)
-- 
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