diff --git a/gateware/e1-tracer/doc/mem-map.md b/gateware/e1-tracer/doc/mem-map.md
index 06cfad0..aa79948 100644
--- a/gateware/e1-tracer/doc/mem-map.md
+++ b/gateware/e1-tracer/doc/mem-map.md
@@ -156,21 +156,43 @@
 
 Write to this register with bit 2 set will trigger a FPGA reload of the selected image.
 
-#### E1 tick channel 0/1 (Read Only, addr `0x04` / `0x05`)
+#### E1 tick source select (Write Only, addr `0x04`)
 
 ```text
 ,-----------------------------------------------------------------------------------------------,
 |31|30|29|28|27|26|25|24|23|22|21|20|19|18|17|16|15|14|13|12|11|10| 9| 8| 7| 6| 5| 4| 3| 2| 1| 0|
 |-----------------------------------------------------------------------------------------------|
-|                      /                        |                   rx_tick                     |
+|                     /                   |ts[1]|                   /                     |ts[0]|
 '-----------------------------------------------------------------------------------------------'
 
- * [15:0] - rx_tick
+ * [17:16] - ts[1] : Tick Source for channel 1
+ * [ 1: 0] - ts[0] : Tick Source for channel 0
 ```
 
-An internal counter is incremented at every bit received by the corresponding E1 channel. That
-counter value is then captured at every USB Start-of-Frame packet and the last captured value
-made available here.
+Selects the tick source for the counters below for each E1 channel.
+Available sources are :
+
+* `0`: (reserved)
+* `1`: (reserved)
+* `2`: RX Sample, for every bit received
+* `3`: RX One, for every `1` bit received
+
+#### E1 tick counters (Read Only, addr `0x04`)
+
+```text
+,-----------------------------------------------------------------------------------------------,
+|31|30|29|28|27|26|25|24|23|22|21|20|19|18|17|16|15|14|13|12|11|10| 9| 8| 7| 6| 5| 4| 3| 2| 1| 0|
+|-----------------------------------------------------------------------------------------------|
+|                  chan[1]                      |                   chan[0]                     |
+'-----------------------------------------------------------------------------------------------'
+
+ * [31:16] - chan[1] : Tick counter for channel 1
+ * [15: 0] - chan[0] : Tick counter for channel 0
+```
+
+An internal counter is incremented at every E1 tick (tick source selected above) for each E1
+channel. That counter value is then captured at every USB Start-of-Frame packet and the last
+captured value made available here.
 
 #### Time (Read Only, addr `0x07`)
 
diff --git a/gateware/e1-tracer/rtl/misc.v b/gateware/e1-tracer/rtl/misc.v
index e39a787..5d1c1f4 100644
--- a/gateware/e1-tracer/rtl/misc.v
+++ b/gateware/e1-tracer/rtl/misc.v
@@ -16,7 +16,7 @@
 	input  wire        btn,
 
 	// Ticks
-	input  wire  [1:0] tick_e1_rx,
+	input  wire  [7:0] tick_e1,
 	input  wire        tick_usb_sof,
 
 	// Reset request
@@ -43,9 +43,13 @@
 	// Bus
 	wire bus_clr;
 	reg  bus_we_boot;
+	reg  bus_we_tick_sel;
 
 	// Counters
-	wire [15:0] cap_e1_rx[0:1];
+	reg   [1:0] tick_e1_sel[0:1];
+	wire  [1:0] tick_e1_mux;
+
+	wire [15:0] cap_e1[0:1];
 	wire [31:0] cnt_time;
 
 	// Boot
@@ -64,10 +68,13 @@
 
 	// Write enables
 	always @(posedge clk)
-		if (bus_clr | ~wb_we)
-			bus_we_boot <= 1'b0;
-		else
-			bus_we_boot <= wb_addr == 4'h0;
+		if (bus_clr | ~wb_we) begin
+			bus_we_boot     <= 1'b0;
+			bus_we_tick_sel <= 1'b0;
+		end else begin
+			bus_we_boot     <= wb_addr == 4'h0;
+			bus_we_tick_sel <= wb_addr == 4'h4;
+		end
 
 	// Read mux
 	always @(posedge clk)
@@ -75,8 +82,7 @@
 			wb_rdata <= 32'h00000000;
 		else
 			case (wb_addr[3:0])
-				4'h4:    wb_rdata <= { 16'h000, cap_e1_rx[0] };
-				4'h5:    wb_rdata <= { 16'h000, cap_e1_rx[1] };
+				4'h4:    wb_rdata <= { cap_e1[1], cap_e1[0] };
 				4'h7:    wb_rdata <= cnt_time;
 				default: wb_rdata <= 32'hxxxxxxxx;
 			endcase
@@ -86,12 +92,21 @@
 	// --------
 
 	// E1 ticks
+	always @(posedge clk)
+		if (bus_we_tick_sel) begin
+			tick_e1_sel[1] <= wb_wdata[17:16];
+			tick_e1_sel[0] <= wb_wdata[ 1: 0];
+		end
+
+	assign tick_e1_mux[0] = tick_e1[{1'b0, tick_e1_sel[0]}];
+	assign tick_e1_mux[1] = tick_e1[{1'b1, tick_e1_sel[1]}];
+
 	capcnt #(
 		.W(16)
 	) e1_cnt_I[1:0] (
 		.cnt_cur (),
-		.cnt_cap ({cap_e1_rx[1],  cap_e1_rx[0] }),
-		.inc     ({tick_e1_rx[1], tick_e1_rx[0]}),
+		.cnt_cap ({      cap_e1[1],      cap_e1[0] }),
+		.inc     ({ tick_e1_mux[1], tick_e1_mux[0] }),
 		.cap     (tick_usb_sof),
 		.clk     (clk),
 		.rst     (rst)
diff --git a/gateware/e1-tracer/rtl/top.v b/gateware/e1-tracer/rtl/top.v
index 0e76c5a..8e1d67b 100644
--- a/gateware/e1-tracer/rtl/top.v
+++ b/gateware/e1-tracer/rtl/top.v
@@ -80,7 +80,7 @@
 	wire [(WB_N*32)-1:0] wb_rdata_flat;
 
 	// Ticks
-	wire [1:0] tick_e1_rx;
+	wire [7:0] tick_e1;
 	wire       tick_usb_sof;
 
 	// Clocks / Reset
@@ -136,7 +136,7 @@
 		.wb_m_we      (wb_we),
 		.wb_m_cyc     (wb_cyc),
 		.wb_m_ack     (wb_ack),
-		.tick_e1_rx   (tick_e1_rx),
+		.tick_e1      (tick_e1),
 		.tick_usb_sof (tick_usb_sof),
 		.clk_sys      (clk_sys),
 		.rst_sys      (rst_sys),
@@ -167,7 +167,7 @@
 
 	misc misc_I (
 		.btn          (btn),
-		.tick_e1_rx   (tick_e1_rx),
+		.tick_e1      (tick_e1),
 		.tick_usb_sof (tick_usb_sof),
 		.rst_req      (rst_req),
 		.wb_addr      (wb_addr[7:0]),