Finished support for separating counters with 4- and 3-bit input muxes. This means that RC oscillator pre-divider value of 12 now works reliably without needing LOC constraints. Fixes #83.

azonenberg · azonenberg · commit 49aa66e3680e · 2017-05-21T21:51:20.000-07:00
diff --git a/doc/gp4-hdl.tex b/doc/gp4-hdl.tex
@@ -219,7 +219,7 @@ \subsection{\namestyle{gp4par} Device Limitations}
 
 \begin{itemize}
 \item Counters: Delay, edge detector, PWM, wake-sleep mode, counter cascading.
-All clock sources other than on-chip oscillators. Pre-divider value of 12.
+All clock sources other than on-chip oscillators.
 \item ADC
 \item DAC: Inputs from DCMP.
 \item Wake-Sleep
diff --git a/src/gp4par/make_graphs.cpp b/src/gp4par/make_graphs.cpp
@@ -383,6 +383,22 @@ bool MakeNetlistNodes(
 			return false;
 		}
 
+		//Special label remapping for counters!
+		//If a GP_COUNT8 asks for a pre-divider of 12, change the label to GP_COUNT8_X4INPUT
+		//TODO: see if any other pre-divider values are special?
+		//Note that GP_COUNT8_ADV always has a 4-bit input mux, as does a GP_COUNT14_ADV
+		//so no special casing needed for those
+		if(cell->m_type == "GP_COUNT8")
+		{
+			//See if we have CLKIN_DIVIDE == 12
+			if(cell->m_parameters["CLKIN_DIVIDE"] == "12")
+			{
+				LogDebug("Found CLKIN_DIVIDE = 12 on GP_COUNT8 instance %s, changing to GP_COUNT8_X4INPUT\n",
+					cell->m_name.c_str());
+				label = ilmap["GP_COUNT8_X4INPUT"];
+			}
+		}
+
 		//Create a node for the cell
 		PARGraphNode* nnode = new PARGraphNode(label, cell);
 		cell->m_parnode = nnode;
@@ -551,7 +567,6 @@ void MakeDeviceNodes(
 	uint32_t count8_adv_label = AllocateLabel(ngraph, dgraph, lmap, "GP_COUNT8_ADV");
 	uint32_t count14_label = AllocateLabel(ngraph, dgraph, lmap, "GP_COUNT14");
 	uint32_t count14_adv_label = AllocateLabel(ngraph, dgraph, lmap, "GP_COUNT14_ADV");
-	uint32_t count14_x4input_label = AllocateLabel(ngraph, dgraph, lmap, "GP_COUNT14_X4INPUT");
 	uint32_t count8_x4input_label = AllocateLabel(ngraph, dgraph, lmap, "GP_COUNT8_X4INPUT");
 	for(unsigned int i=0; i<device->GetCounterCount(); i++)
 	{
@@ -570,7 +585,7 @@ void MakeDeviceNodes(
 				node->AddAlternateLabel(count8_label);
 				node->AddAlternateLabel(count14_label);
 				node->AddAlternateLabel(count8_x4input_label);
-				node->AddAlternateLabel(count14_x4input_label);
+				//There's no GP_COUNT14_X4INPUT because all GP_COUNT14_ADV cells have 4-bit input muxes
 			}
 			else
 			{
diff --git a/tests/greenpak4/slg46620v/Count12.v b/tests/greenpak4/slg46620v/Count12.v
@@ -56,7 +56,7 @@ module Count12(dout);
 
 	GP_COUNT8 #(
 		.RESET_MODE("LEVEL"),
-		.COUNT_TO(12),
+		.COUNT_TO(32),
 		.CLKIN_DIVIDE(12)
 	) cnt (
 		.CLK(clk_6khz_cnt),
