// For reading TI tags, we need to place the FPGA in pass through mode
// and pass everything through to the ARM
//-----------------------------------------------------------------------------
+// iZsh <izsh at fail0verflow.com>, June 2014
module lo_passthru(
- pck0, ck_1356meg, ck_1356megb,
- pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4,
- adc_d, adc_clk,
- ssp_frame, ssp_din, ssp_dout, ssp_clk,
- cross_hi, cross_lo,
- dbg, divisor
+ input pck_divclk,
+ output pwr_lo, output pwr_hi,
+ output pwr_oe1, output pwr_oe2, output pwr_oe3, output pwr_oe4,
+ output adc_clk,
+ output ssp_din, input ssp_dout,
+ input cross_lo,
+ output dbg
);
- input pck0, ck_1356meg, ck_1356megb;
- output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
- input [7:0] adc_d;
- output adc_clk;
- input ssp_dout;
- output ssp_frame, ssp_din, ssp_clk;
- input cross_hi, cross_lo;
- output dbg;
- input [7:0] divisor;
-
-reg [7:0] pck_divider;
-reg ant_lo;
-
-// this task runs on the rising egde of pck0 clock (24Mhz) and creates ant_lo
-// which is high for (divisor+1) pck0 cycles and low for the same duration
-// ant_lo is therefore a 50% duty cycle clock signal with a frequency of
-// 12Mhz/(divisor+1) which drives the antenna as well as the ADC clock adc_clk
-always @(posedge pck0)
-begin
- if(pck_divider == divisor[7:0])
- begin
- pck_divider <= 8'd0;
- ant_lo = !ant_lo;
- end
- else
- begin
- pck_divider <= pck_divider + 1;
- end
-end
// the antenna is modulated when ssp_dout = 1, when 0 the
// antenna drivers stop modulating and go into listen mode
assign pwr_oe1 = ssp_dout;
assign pwr_oe2 = ssp_dout;
assign pwr_oe4 = ssp_dout;
-assign pwr_lo = ant_lo && ssp_dout;
+assign pwr_lo = pck_divclk && ssp_dout;
assign pwr_hi = 1'b0;
assign adc_clk = 1'b0;
assign ssp_din = cross_lo;