diff --git a/gateware/icE1usb-proto/rtl/sysmgr.v b/gateware/icE1usb-proto/rtl/sysmgr.v
new file mode 100644
index 0000000..6ae9721
--- /dev/null
+++ b/gateware/icE1usb-proto/rtl/sysmgr.v
@@ -0,0 +1,100 @@
+/*
+ * sysmgr.v
+ *
+ * vim: ts=4 sw=4
+ *
+ * System Clock / Reset generation
+ *
+ * Copyright (C) 2019-2020  Sylvain Munaut <tnt@246tNt.com>
+ * SPDX-License-Identifier: CERN-OHL-S-2.0
+ */
+
+`default_nettype none
+
+module sysmgr (
+	input  wire clk_in,
+	input  wire rst_in,
+	output wire clk_sys,
+	output wire rst_sys,
+	output wire clk_48m,
+	output wire rst_48m
+);
+
+	// Signals
+	wire pll_lock;
+	wire pll_reset_n;
+
+	wire clk_30m72_i;
+	wire rst_30m72_i;
+	wire clk_48m_i;
+	reg  rst_48m_i;
+
+	reg [3:0] rst_cnt;
+
+	// Global input buffer for 30.72 MHz clock
+	SB_GB_IO #(
+		.PIN_TYPE(6'b000001),
+	) gb_in (
+		.PACKAGE_PIN(clk_in),
+		.GLOBAL_BUFFER_OUTPUT(clk_30m72_i),
+	);
+
+	// PLL instance
+	SB_PLL40_CORE #(
+		.DIVR(4'b0000),
+		.DIVF(7'b0011000),
+		.DIVQ(3'b100),
+		.FILTER_RANGE(3'b011),
+		.FEEDBACK_PATH("SIMPLE"),
+		.DELAY_ADJUSTMENT_MODE_FEEDBACK("FIXED"),
+		.FDA_FEEDBACK(4'b0000),
+		.SHIFTREG_DIV_MODE(2'b00),
+		.PLLOUT_SELECT("GENCLK"),
+		.ENABLE_ICEGATE(1'b0),
+	) pll_I (
+		.REFERENCECLK(clk_30m72_i),
+		.PLLOUTCORE(),
+		.PLLOUTGLOBAL(clk_48m_i),
+		.EXTFEEDBACK(1'b0),
+		.DYNAMICDELAY(8'h00),
+		.RESETB(pll_reset_n),
+		.BYPASS(1'b0),
+		.LATCHINPUTVALUE(1'b0),
+		.LOCK(pll_lock),
+		.SDI(1'b0),
+		.SDO(),
+		.SCLK(1'b0)
+	);
+
+	assign clk_sys = clk_30m72_i;
+	assign clk_48m = clk_48m_i;
+
+	// PLL reset generation
+	assign pll_reset_n = ~rst_in;
+
+	// Logic reset generation
+	always @(posedge clk_30m72_i or negedge pll_lock)
+		if (!pll_lock)
+			rst_cnt <= 4'h0;
+		else if (~rst_cnt[3])
+			rst_cnt <= rst_cnt + 1;
+
+	assign rst_30m72_i = ~rst_cnt[3];
+
+	always @(posedge clk_48m or posedge rst_30m72_i)
+		if (rst_30m72_i)
+			rst_48m_i <= 1'b1;
+		else
+			rst_48m_i <= 1'b0;
+
+	SB_GB rst_sys_gbuf_I (
+		.USER_SIGNAL_TO_GLOBAL_BUFFER(rst_30m72_i),
+		.GLOBAL_BUFFER_OUTPUT(rst_sys)
+	);
+
+	SB_GB rst_48m_gbuf_I (
+		.USER_SIGNAL_TO_GLOBAL_BUFFER(rst_48m_i),
+		.GLOBAL_BUFFER_OUTPUT(rst_48m)
+	);
+
+endmodule // sysmgr