From: Marius Gavrilescu <marius@ieval.ro>
Date: Thu, 22 Mar 2018 20:02:44 +0000 (+0200)
Subject: Discover the PLL and multiply the CLK by 4
X-Git-Url: http://git.ieval.ro/?p=clump.git;a=commitdiff_plain;h=3e7694a3bd6a2d6e2d19a266f807078ab92ad1b7

Discover the PLL and multiply the CLK by 4
---

diff --git a/lisp_processor.pcf b/lisp_processor.pcf
index 92d1b64..9c20287 100644
--- a/lisp_processor.pcf
+++ b/lisp_processor.pcf
@@ -17,4 +17,4 @@ set_io uart_tx 8
 set_io uart_rx 9
 
 # 12 MHz clock
-set_io clk 21
+set_io CLKin 21
diff --git a/lisp_processor.v b/lisp_processor.v
index f856aa2..fbc4467 100644
--- a/lisp_processor.v
+++ b/lisp_processor.v
@@ -1,3 +1,4 @@
+`include "pll.v"
 `include "gc.v"
 `include "eval.v"
 `include "reader.v"
@@ -28,7 +29,11 @@
  `define UART_DIVIDE 625
 `endif
 
-module cpu (input clk, output [4:0] led, output uart_tx, input uart_rx);
+module cpu (input CLKin, output [4:0] led, output uart_tx, input uart_rx);
+   wire clk;
+
+   pll pll (.clock_in(CLKin), .clock_out(clk));
+
    wire [12:0] freeptr;
    wire [15:0] E1;
    wire [15:0] E2;
@@ -88,6 +93,6 @@ module cpu (input clk, output [4:0] led, output uart_tx, input uart_rx);
    wire 	  uart_tx_signal;
    wire [7:0] uart_tx_byte;
 
-   // 4800 baud uart
+   // 19200 baud uart
    uart #(.CLOCK_DIVIDE(`UART_DIVIDE)) uart (.clk(clk), .rx(uart_rx), .tx(uart_tx), .transmit(uart_tx_signal), .tx_byte(uart_tx_byte), .received(uart_rx_signal), .rx_byte(uart_rx_byte), .is_receiving(uart_is_receiving), .is_transmitting(uart_is_transmitting), .recv_error (uart_rx_error));
 endmodule
diff --git a/pll.v b/pll.v
new file mode 100644
index 0000000..38745ad
--- /dev/null
+++ b/pll.v
@@ -0,0 +1,33 @@
+/**
+ * PLL configuration
+ *
+ * This Verilog module was generated automatically
+ * using the icepll tool from the IceStorm project.
+ * Use at your own risk.
+ *
+ * Given input frequency:        12.000 MHz
+ * Requested output frequency:   48.000 MHz
+ * Achieved output frequency:    48.000 MHz
+ */
+
+module pll(
+	input  clock_in,
+	output clock_out,
+	output locked
+	);
+
+SB_PLL40_CORE #(
+		.FEEDBACK_PATH("SIMPLE"),
+		.DIVR(4'b0000),		// DIVR =  0
+		.DIVF(7'b0111111),	// DIVF = 63
+		.DIVQ(3'b100),		// DIVQ =  4
+		.FILTER_RANGE(3'b001)	// FILTER_RANGE = 1
+	) uut (
+		.LOCK(locked),
+		.RESETB(1'b1),
+		.BYPASS(1'b0),
+		.REFERENCECLK(clock_in),
+		.PLLOUTCORE(clock_out)
+		);
+
+endmodule