Add CNT area reduction from 0.6e

This commit is contained in:
Zane Kaminski 2024-10-03 18:45:35 -04:00
parent d69358ca8f
commit 02ab10bb5a
2 changed files with 20 additions and 27 deletions

View File

@ -2,7 +2,7 @@ module CNT(
/* FSB clock and E clock inputs */ /* FSB clock and E clock inputs */
input CLK, input C8M, input E, input CLK, input C8M, input E,
/* Refresh request */ /* Refresh request */
output reg RefReq, output reg RefUrg, output reg RefReq, output RefUrg,
/* Reset, button */ /* Reset, button */
output reg nRESout, input nRESin, input nIPL2, output reg nRESout, input nRESin, input nIPL2,
/* Mac PDS bus master control outputs */ /* Mac PDS bus master control outputs */
@ -22,10 +22,6 @@ module CNT(
/* C8M clock synchronization */ /* C8M clock synchronization */
reg [3:0] C8Mr; always @(posedge CLK) C8Mr[3:0] <= { C8Mr[2:0], C8M }; reg [3:0] C8Mr; always @(posedge CLK) C8Mr[3:0] <= { C8Mr[2:0], C8M };
/* NMI and reset synchronization */
reg nIPL2r; always @(posedge CLK) nIPL2r <= nIPL2;
reg nRESr; always @(posedge CLK) nRESr <= nRESin;
/* Timer counts from 0 to 1010 (10) -- 11 states == 14.042 us /* Timer counts from 0 to 1010 (10) -- 11 states == 14.042 us
* Refresh timer sequence * Refresh timer sequence
* | Timer | RefReq | RefUrg | * | Timer | RefReq | RefUrg |
@ -38,46 +34,50 @@ module CNT(
* | 5 0101 | 1 | 0 | * | 5 0101 | 1 | 0 |
* | 6 0110 | 1 | 0 | * | 6 0110 | 1 | 0 |
* | 7 0111 | 1 | 0 | * | 7 0111 | 1 | 0 |
* | 8 1000 | 1 | 0 | * | 8 1000 | 1 | 1 |
* | 9 1001 | 1 | 1 | * | 9 1001 | 1 | 1 |
* | 10 1010 | 1 | 1 | * | 10 1010 | 1 | 1 |
* back to timer==0 * back to timer==0
*/ */
reg [3:0] Timer = 0; reg [3:0] Timer = 0;
wire TimerTC = Timer==10; wire TimerTC = Timer==10;
assign RefUrg = Timer[3];
reg TimerTick; reg TimerTick;
always @(posedge CLK) begin always @(posedge CLK) begin
if (EFall) begin if (EFall) begin
if (TimerTC) Timer <= 0; if (TimerTC) Timer <= 0;
else Timer <= Timer+1; else Timer <= Timer+1;
RefUrg <= Timer==8 || Timer==9;
RefReq <= Timer!=10; RefReq <= Timer!=10;
end end
end end
always @(posedge CLK) TimerTick <= EFall && TimerTC; always @(posedge CLK) TimerTick <= EFall && TimerTC;
/* QoS select latch */ /* QoS select latches */
reg QoSCSr; reg QoSCSr, SndQoSCSr;
always @(posedge CLK) QoSCSr <= (BACT && (QoSCS || SndQoSCS)) || !nRESr; always @(posedge CLK) QoSCSr <= (BACT && QoSCS) || !nRESin;
always @(posedge CLK) SndQoSCSr <= BACT && SndQoSCS;
/* Wait state timer */
reg [3:0] Wait;
always @(posedge CLK) begin
if (!BACT) Wait <= 0;
else Wait <= Wait+1;
end
/* QoS timer /* QoS timer
* In the absence of a QoS trigger, QS==0. * In the absence of a QoS trigger, QS==0.
* When Qos triggered, QS is set to 1 and counts 1, 2, 3, 0. * When Qos triggered, QS is set to 1 and counts 1, 2, 3, 0.
* While QS!=0, QoS is enabled. * While QS!=0, QoS is enabled.
* QoS enable period is 28.124 us - 42.240 us */ * QoS enable period is 196.588 us - 210.630 us */
reg [3:0] QS; reg [3:0] QS;
always @(posedge CLK) begin always @(posedge CLK) begin
if (QoSCSr) QS <= 15; if (SndQoSCSr || QoSCSr) QS <= 15;
else if (QS==0) QS <= 0; else if (QS==0) QS <= 0;
else if (TimerTick) QS <= QS-1; else if (TimerTick) QS <= QS-1;
end end
/* QoS enable control */ /* QoS enable control */
always @(posedge CLK) if (!BACT) QoSEN <= QS!=0; always @(posedge CLK) if (!BACT) QoSEN <= QS!=0;
/* Sound QoS select latch */
reg SndQoSCSr;
always @(posedge CLK) SndQoSCSr <= BACT && SndQoSCS;
/* Sound QoS timer */ /* Sound QoS timer */
reg [1:0] SndQS; reg [1:0] SndQS;
@ -88,17 +88,10 @@ module CNT(
else if (TimerTick) SndQS <= SndQS-1; else if (TimerTick) SndQS <= SndQS-1;
end end
/* Wait state timer */
reg [3:0] Wait;
always @(posedge CLK) begin
if (!BACT) Wait <= 0;
else Wait <= Wait+1;
end
/* Sound QoS ready control */ /* Sound QoS ready control */
always @(posedge CLK) begin always @(posedge CLK) begin
if (!BACT) SndQoSReady <= SndQS==0; if (!BACT) SndQoSReady <= SndQS==0;
else if (QoSCSr && !SndQoSCSr) SndQoSReady <= 1; else if (QoSCSr) SndQoSReady <= 1;
else if (Wait==15) SndQoSReady <= 1; else if (Wait==15) SndQoSReady <= 1;
end end
@ -124,7 +117,7 @@ module CNT(
else case (IS[1:0]) else case (IS[1:0])
0: if (LTimerTick) IS <= 1; 0: if (LTimerTick) IS <= 1;
1: if (LTimerTick) IS <= 2; 1: if (LTimerTick) IS <= 2;
2: if (LTimerTick && nIPL2r) IS <= 3; 2: if (LTimerTick && nIPL2) IS[0] <= 1;
3: IS <= 3; 3: IS <= 3;
endcase endcase
end end
@ -139,7 +132,7 @@ module CNT(
end 2: begin end 2: begin
AoutOE <= 0; AoutOE <= 0;
nRESout <= 0; nRESout <= 0;
if (!nIPL2r) nBR_IOB <= 1; // Disable bus request if NMI pressed if (!nIPL2) nBR_IOB <= 1; // Disable bus request if NMI pressed
end 3: begin end 3: begin
AoutOE <= !nBR_IOB; AoutOE <= !nBR_IOB;
if (LTimerTick) nRESout <= 1; // Release reset after a while if (LTimerTick) nRESout <= 1; // Release reset after a while

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@ -49,7 +49,7 @@ module CS(
wire SndRAMCSWR = VidRAMCSWR64k && ( wire SndRAMCSWR = VidRAMCSWR64k && (
((A[15:12]==4'hF) && (A[11:8]==4'hD || A[11:8]==4'hE || A[11:8]==4'hF)) || ((A[15:12]==4'hF) && (A[11:8]==4'hD || A[11:8]==4'hE || A[11:8]==4'hF)) ||
((A[15:12]==4'hA) && (A[11:8]==4'h1 || A[11:8]==4'h2 || A[11:8]==4'h3))); ((A[15:12]==4'hA) && (A[11:8]==4'h1 || A[11:8]==4'h2 || A[11:8]==4'h3)));
assign QoSCS = IACKCS || VIACS || IWMCS || SCCCS || SCSICS || SndRAMCSWR; assign QoSCS = IACKCS || VIACS || IWMCS || SCCCS || SCSICS;
assign SndQoSCS = SndRAMCSWR; assign SndQoSCS = SndRAMCSWR;
/* Select signals - IOB domain */ /* Select signals - IOB domain */