adc_d, adc_clk,\r
ssp_frame, ssp_din, ssp_dout, ssp_clk,\r
cross_hi, cross_lo,\r
- dbg\r
+ dbg,
+ divisor\r
);\r
input pck0, ck_1356meg, ck_1356megb;\r
output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;\r
input ssp_dout;\r
output ssp_frame, ssp_din, ssp_clk;\r
input cross_hi, cross_lo;\r
- output dbg;\r
+ output dbg;
+ input [7:0] divisor;\r
\r
// No logic, straight through.\r
assign pwr_oe3 = 1'b0;\r
assign pwr_oe4 = ssp_dout;\r
assign ssp_clk = cross_lo;\r
assign pwr_lo = 1'b0;\r
-assign adc_clk = 1'b0;\r
assign pwr_hi = 1'b0;\r
-assign dbg = cross_lo;\r
+assign dbg = ssp_frame;\r
+
+// Divide the clock to be used for the ADC
+reg [7:0] pck_divider;
+reg clk_state;
+\r
+always @(posedge pck0)\r
+begin\r
+ if(pck_divider == divisor[7:0])\r
+ begin\r
+ pck_divider <= 8'd0;
+ clk_state = !clk_state;\r
+ end\r
+ else\r
+ begin\r
+ pck_divider <= pck_divider + 1;\r
+ end\r
+end\r
+
+assign adc_clk = ~clk_state;
+
+// Toggle the output with hysteresis
+// Set to high if the ADC value is above 200
+// Set to low if the ADC value is below 64
+reg is_high;
+reg is_low;
+reg output_state;
+
+always @(posedge pck0)\r
+begin\r
+ if((pck_divider == 8'd7) && !clk_state) begin
+ is_high = (adc_d >= 8'd200);
+ is_low = (adc_d <= 8'd64);
+ end
+end
+
+always @(posedge is_high or posedge is_low)
+begin
+ if(is_high)
+ output_state <= 1'd1;
+ else if(is_low)
+ output_state <= 1'd0;
+end
+
+assign ssp_frame = output_state;
\r
endmodule\r