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https://github.com/tillitis/tillitis-key1.git
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FPGA: Increase clock frequency to 21 MHz
Signed-off-by: Joachim Strömbergson <joachim@assured.se>
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@ -1 +1 @@
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24e642b0dc78a7dbf4cd87c223dd26eefb1ad444c96858e1c2b373f35701ccc0 application_fpga.bin
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42746c6d9d879ad975874fb51b3d4e031578dac9a0e7ddd4b10a1d3efa34c6c7 application_fpga.bin
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@ -83,10 +83,10 @@ module uart(
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// The default bit rate is based on target clock frequency
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// The default bit rate is based on target clock frequency
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// divided by the bit rate times in order to hit the
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// divided by the bit rate times in order to hit the
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// center of the bits. I.e.
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// center of the bits. I.e.
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// Clock: 18 MHz, 62500 bps
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// Clock: 21 MHz, 62500 bps
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// Divisor = 18E6 / 62500 = 288
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// Divisor = 21E6 / 62500 = 336
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// This also satisfies 1E6 % bps == 0 for the CH552 MCU used for USB-serial
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// This also satisfies 1E6 % bps == 0 for the CH552 MCU used for USB-serial
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localparam DEFAULT_BIT_RATE = 16'd288;
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localparam DEFAULT_BIT_RATE = 16'd336;
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localparam DEFAULT_DATA_BITS = 4'h8;
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localparam DEFAULT_DATA_BITS = 4'h8;
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localparam DEFAULT_STOP_BITS = 2'h1;
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localparam DEFAULT_STOP_BITS = 2'h1;
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@ -70,14 +70,14 @@ module clk_reset_gen #(parameter RESET_CYCLES = 200)
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//
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//
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// F_pllout == (F_referenceclk * (DIVF + 1)) / (2^DIVQ * (DIVR + 1))
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// F_pllout == (F_referenceclk * (DIVF + 1)) / (2^DIVQ * (DIVR + 1))
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//
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//
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// Given the 12 MHz HFOSC clock set above, we get a final 18 MHz:
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// Given the 12 MHz HFOSC clock set above, we get a final 21 MHz:
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//
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//
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// (12000000 * (47 + 1)) / (2^5 * (0 + 1)) = 18000000
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// (12000000 * (55 + 1)) / (2^5 * (0 + 1)) = 21000000
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SB_PLL40_CORE #(
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SB_PLL40_CORE #(
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.FEEDBACK_PATH("SIMPLE"),
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.FEEDBACK_PATH("SIMPLE"),
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.DIVR(4'b0000), // DIVR = 0
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.DIVR(4'd0), // DIVR = 0
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.DIVF(7'b0101111), // DIVF = 47
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.DIVF(7'd55), // DIVF = 55
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.DIVQ(3'b101), // DIVQ = 5
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.DIVQ(3'd5), // DIVQ = 5
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.FILTER_RANGE(3'b001) // FILTER_RANGE = 1
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.FILTER_RANGE(3'b001) // FILTER_RANGE = 1
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) pll_inst (
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) pll_inst (
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.RESETB(1'b1),
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.RESETB(1'b1),
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