Merge pull request #201 from timvideos/hdmi-debugging

Adding HDMI debugging back in.
timvideos · Jan 28, 2016 · 1a0b637 · 1a0b637
2 parents 893f1c8 + 10d358e
commit 1a0b637
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diff --git a/firmware/lm32/ci.c b/firmware/lm32/ci.c
@@ -630,6 +630,18 @@ void ci_service(void)
 		token = get_token(&str);
 		if(strcmp(token, "pll") == 0)
 			debug_pll();
+#ifdef CSR_HDMI_IN0_BASE
+		else if(strcmp(token, "input0") == 0) {
+			hdmi_in0_debug = !hdmi_in0_debug;
+			printf("HDMI Input 0 debug %s\r\n", hdmi_in0_debug ? "on" : "off");
+		}
+#endif
+#ifdef CSR_HDMI_IN1_BASE
+		else if(strcmp(token, "input1") == 0) {
+			hdmi_in1_debug = !hdmi_in1_debug;
+			printf("HDMI Input 1 debug %s\r\n", hdmi_in1_debug ? "on" : "off");
+		}
+#endif
 		else if(strcmp(token, "ddr") == 0)
 			debug_ddr();
 		else if(strcmp(token, "dna") == 0)

diff --git a/gateware/hdmi_in/wer.py b/gateware/hdmi_in/wer.py
@@ -7,6 +7,12 @@
 
 
 class WER(Module, AutoCSR):
+    """Word Error Rate calculation module.
+
+    https://en.wikipedia.org/wiki/Transition-minimized_differential_signaling
+
+    """
+
     def __init__(self, period_bits=24):
         self.data = Signal(10)
         self._update = CSR()
@@ -20,11 +26,15 @@ def __init__(self, period_bits=24):
         self.sync.pix += data_r.eq(self.data[:9])
 
         # pipeline stage 2
+	# Count the number of transitions in the TMDS word.
         transitions = Signal(8)
         self.comb += [transitions[i].eq(data_r[i] ^ data_r[i+1]) for i in range(8)]
         transition_count = Signal(max=9)
         self.sync.pix += transition_count.eq(optree("+", [transitions[i] for i in range(8)]))
 
+	# Control data characters are designed to have a large number (7) of
+	# transitions to help the receiver synchronize its clock with the
+	# transmitter clock.
         is_control = Signal()
         self.sync.pix += is_control.eq(optree("|", [data_r == ct for ct in control_tokens]))