X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/94ad01bfba1c29747f9c42942bbec6b834695ef2..2a537311063d3e49479ff4cc8b94287a10c37266:/fpga/hi_simulate.v

diff --git a/fpga/hi_simulate.v b/fpga/hi_simulate.v
index c04ade80..78650c4a 100644
--- a/fpga/hi_simulate.v
+++ b/fpga/hi_simulate.v
@@ -50,12 +50,29 @@ begin
     else if(~(| adc_d[7:5])) after_hysteresis = 1'b0;
 end
 
-// Divide 13.56 MHz by 32 to produce the SSP_CLK
-// The register is bigger to allow higher division factors of up to /128
-reg [6:0] ssp_clk_divider;
+
+// Divide 13.56 MHz to produce various frequencies for SSP_CLK
+// and modulation. 11 bits allow for factors of up to /128.
+reg [10:0] ssp_clk_divider;
+
 always @(posedge adc_clk)
     ssp_clk_divider <= (ssp_clk_divider + 1);
-assign ssp_clk = ssp_clk_divider[4];
+
+reg ssp_clk;
+
+always @(negedge adc_clk)
+begin
+    if(mod_type == 3'b101)
+      // Get bit every at 53KHz (every 8th carrier bit of 424kHz)
+      ssp_clk <= ssp_clk_divider[7];
+    else if(mod_type == 3'b010)
+      // Get next bit at 212kHz
+      ssp_clk <= ssp_clk_divider[5];
+    else
+      // Get next bit at 424Khz
+      ssp_clk <= ssp_clk_divider[4];
+end
+
 
 // Divide SSP_CLK by 8 to produce the byte framing signal; the phase of
 // this is arbitrary, because it's just a bitstream.
@@ -69,6 +86,7 @@ reg [2:0] ssp_frame_divider_from_arm;
 always @(negedge ssp_clk)
     ssp_frame_divider_from_arm <= (ssp_frame_divider_from_arm + 1);
 
+
 reg ssp_frame;
 always @(ssp_frame_divider_to_arm or ssp_frame_divider_from_arm or mod_type)
     if(mod_type == 3'b000) // not modulating, so listening, to ARM
@@ -81,7 +99,7 @@ reg ssp_din;
 always @(posedge ssp_clk)
     ssp_din = after_hysteresis;
 
-// Modulating carrier frequency is fc/16, reuse ssp_clk divider for that
+// Modulating carrier frequency is fc/64 (212kHz) to fc/16 (848kHz). Reuse ssp_clk divider for that.
 reg modulating_carrier;
 always @(mod_type or ssp_clk or ssp_dout)
     if(mod_type == 3'b000)
@@ -89,9 +107,9 @@ always @(mod_type or ssp_clk or ssp_dout)
     else if(mod_type == 3'b001)
         modulating_carrier <= ssp_dout ^ ssp_clk_divider[3]; // XOR means BPSK
     else if(mod_type == 3'b010)
-	modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
-    else if(mod_type == 3'b100)
-	modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
+        modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
+    else if(mod_type == 3'b100 || mod_type == 3'b101)
+        modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
     else
         modulating_carrier <= 1'b0;                           // yet unused
 
@@ -106,9 +124,6 @@ assign pwr_oe4 = modulating_carrier;
 // This one is always on, so that we can watch the carrier.
 assign pwr_oe3 = 1'b0;
 
-assign dbg = after_hysteresis;
-//reg dbg;
-//always @(ssp_dout)
-//    dbg <= ssp_dout;
+assign dbg = ssp_din;
 
 endmodule