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Remove magic numbers

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Signed-off-by: Alex Forencich <alex@alexforencich.com>
This commit is contained in:
Alex Forencich 2022-07-22 18:39:21 -07:00
parent 4a16c9070b
commit db881ed551
2 changed files with 12 additions and 8 deletions
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6
rtl/ptp_clock.v
View File

@ -96,6 +96,8 @@ module ptp_clock #
parameter INC_NS_WIDTH = $clog2(2**PERIOD_NS_WIDTH + 2**OFFSET_NS_WIDTH + 2**DRIFT_NS_WIDTH);
localparam [30:0] NS_PER_S = 31'd1_000_000_000;
reg [PERIOD_NS_WIDTH-1:0] period_ns_reg = PERIOD_NS;
reg [FNS_WIDTH-1:0] period_fns_reg = PERIOD_FNS;
@ -252,13 +254,13 @@ always @(posedge clk) begin
// if the overflow lookahead did not borrow, one second has elapsed
// increment seconds field, pre-compute both normal increment and overflow values
{ts_96_ns_inc_reg, ts_96_fns_inc_reg} <= {ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} + {ts_inc_ns_reg, ts_inc_fns_reg};
{ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} <= {ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} + {ts_inc_ns_reg, ts_inc_fns_reg} - {31'd1_000_000_000, {FNS_WIDTH{1'b0}}};
{ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} <= {ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} + {ts_inc_ns_reg, ts_inc_fns_reg} - {NS_PER_S, {FNS_WIDTH{1'b0}}};
{ts_96_ns_reg, ts_96_fns_reg} <= {ts_96_ns_ovf_reg, ts_96_fns_ovf_reg};
ts_96_s_reg <= ts_96_s_reg + 1;
end else begin
// no increment seconds field, pre-compute both normal increment and overflow values
{ts_96_ns_inc_reg, ts_96_fns_inc_reg} <= {ts_96_ns_inc_reg, ts_96_fns_inc_reg} + {ts_inc_ns_reg, ts_inc_fns_reg};
{ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} <= {ts_96_ns_inc_reg, ts_96_fns_inc_reg} + {ts_inc_ns_reg, ts_inc_fns_reg} - {31'd1_000_000_000, {FNS_WIDTH{1'b0}}};
{ts_96_ns_ovf_reg, ts_96_fns_ovf_reg} <= {ts_96_ns_inc_reg, ts_96_fns_inc_reg} + {ts_inc_ns_reg, ts_inc_fns_reg} - {NS_PER_S, {FNS_WIDTH{1'b0}}};
{ts_96_ns_reg, ts_96_fns_reg} <= {ts_96_ns_inc_reg, ts_96_fns_inc_reg};
ts_96_s_reg <= ts_96_s_reg;
end

14
rtl/ptp_clock_cdc.v
View File

@ -89,6 +89,8 @@ parameter SAMPLE_ACC_WIDTH = LOG_SAMPLE_SYNC_RATE+2;
parameter DEST_SYNC_LOCK_WIDTH = 7;
parameter PTP_LOCK_WIDTH = 8;
localparam [30:0] NS_PER_S = 31'd1_000_000_000;
reg [NS_WIDTH-1:0] period_ns_reg = 0, period_ns_next;
reg [FNS_WIDTH-1:0] period_fns_reg = 0, period_fns_next;
@ -574,13 +576,13 @@ always @* begin
// if the overflow lookahead did not borrow, one second has elapsed
// increment seconds field, pre-compute both normal increment and overflow values
{ts_ns_inc_next, ts_fns_inc_next} = {ts_ns_ovf_reg, ts_fns_ovf_reg} + {period_ns_reg, period_fns_reg};
{ts_ns_ovf_next, ts_fns_ovf_next} = {ts_ns_ovf_reg, ts_fns_ovf_reg} + {period_ns_reg, period_fns_reg} - {31'd1_000_000_000, {FNS_WIDTH{1'b0}}};
{ts_ns_ovf_next, ts_fns_ovf_next} = {ts_ns_ovf_reg, ts_fns_ovf_reg} + {period_ns_reg, period_fns_reg} - {NS_PER_S, {FNS_WIDTH{1'b0}}};
{ts_ns_next, ts_fns_next} = {ts_ns_ovf_reg, ts_fns_ovf_reg};
ts_s_next = ts_s_next + 1;
end else begin
// no increment seconds field, pre-compute both normal increment and overflow values
{ts_ns_inc_next, ts_fns_inc_next} = {ts_ns_inc_reg, ts_fns_inc_reg} + {period_ns_reg, period_fns_reg};
{ts_ns_ovf_next, ts_fns_ovf_next} = {ts_ns_inc_reg, ts_fns_inc_reg} + {period_ns_reg, period_fns_reg} - {31'd1_000_000_000, {FNS_WIDTH{1'b0}}};
{ts_ns_ovf_next, ts_fns_ovf_next} = {ts_ns_inc_reg, ts_fns_inc_reg} + {period_ns_reg, period_fns_reg} - {NS_PER_S, {FNS_WIDTH{1'b0}}};
{ts_ns_next, ts_fns_next} = {ts_ns_inc_reg, ts_fns_inc_reg};
ts_s_next = ts_s_next;
end
@ -639,14 +641,14 @@ always @* begin
ts_ns_diff_corr_next = ts_ns_diff_reg[16:0];
ts_fns_diff_corr_next = ts_fns_diff_reg;
diff_corr_valid_next = 1'b1;
end else if ($signed(ts_s_diff_reg) == 1 && ts_ns_diff_reg[30:16] == 15'h4465) begin
end else if ($signed(ts_s_diff_reg) == 1 && ts_ns_diff_reg[30:16] == ~NS_PER_S[30:16]) begin
// difference is small with 1 second difference; adjust and slew
ts_ns_diff_corr_next = ts_ns_diff_reg[16:0] + 17'h0ca00;
ts_ns_diff_corr_next = ts_ns_diff_reg[16:0] + NS_PER_S[16:0];
ts_fns_diff_corr_next = ts_fns_diff_reg;
diff_corr_valid_next = 1'b1;
end else if ($signed(ts_s_diff_reg) == -1 && ts_ns_diff_reg[30:16] == 15'h3b9a) begin
end else if ($signed(ts_s_diff_reg) == -1 && ts_ns_diff_reg[30:16] == NS_PER_S[30:16]) begin
// difference is small with 1 second difference; adjust and slew
ts_ns_diff_corr_next = ts_ns_diff_reg[16:0] - 17'h0ca00;
ts_ns_diff_corr_next = ts_ns_diff_reg[16:0] - NS_PER_S[16:0];
ts_fns_diff_corr_next = ts_fns_diff_reg;
diff_corr_valid_next = 1'b1;
end else begin