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Output read data on falling edge to get more hold time

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This commit is contained in:
Zane Kaminski 2021-04-21 09:19:57 -04:00
parent a3517bf054
commit 7b4a492e6c
2 changed files with 84 additions and 64 deletions
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134
Docs.sch
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@ -19,22 +19,14 @@ Text Notes 1450 650 2 50 ~ 0
C25M
Text Notes 1450 800 2 50 ~ 0
PHI0
Wire Wire Line
1600 650 1600 550
Wire Wire Line
1700 550 1600 550
Wire Wire Line
1700 650 1700 550
Wire Wire Line
1800 650 1700 650
Wire Wire Line
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Wire Wire Line
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Wire Wire Line
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Wire Wire Line
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2000 650 1900 650
Wire Wire Line
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Wire Wire Line
@ -51,14 +43,14 @@ Wire Wire Line
2300 550 2300 650
Wire Wire Line
2300 650 2400 650
Wire Wire Line
2400 650 2400 550
Wire Wire Line
2400 550 2500 550
Wire Wire Line
2500 550 2500 650
Wire Wire Line
2500 650 2600 650
Wire Wire Line
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Wire Wire Line
2600 550 2700 550
Wire Wire Line
@ -156,17 +148,7 @@ Wire Wire Line
Wire Wire Line
5000 650 5000 550
Wire Wire Line
4050 800 5650 800
Wire Wire Line
4000 700 4050 800
Wire Wire Line
1550 800 1600 800
Wire Wire Line
1650 700 4000 700
Wire Wire Line
1600 800 1650 700
Wire Wire Line
1600 650 1550 650
5000 550 5100 550
Wire Wire Line
5100 550 5100 650
Wire Wire Line
@ -174,7 +156,15 @@ Wire Wire Line
Wire Wire Line
5200 650 5200 550
Wire Wire Line
5000 550 5100 550
4300 800 5850 800
Wire Wire Line
4250 700 4300 800
Wire Wire Line
1600 800 1900 800
Wire Wire Line
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Wire Wire Line
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Wire Wire Line
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Wire Wire Line
@ -184,11 +174,19 @@ Wire Wire Line
Wire Wire Line
5200 550 5300 550
Wire Wire Line
1550 850 2600 850
5500 550 5500 650
Wire Wire Line
2600 850 2650 950
5500 650 5600 650
Wire Wire Line
2650 950 4050 950
5600 650 5600 550
Wire Wire Line
5400 550 5500 550
Wire Wire Line
1600 850 2800 850
Wire Wire Line
2800 850 2850 950
Wire Wire Line
2850 950 4250 950
Text Notes 1450 950 2 50 ~ 0
~DEVSEL~
Text Notes 3100 2450 0 50 ~ 0
@ -766,47 +764,31 @@ Wire Wire Line
Text Notes 1450 1400 2 50 ~ 0
PHI0r3
Wire Wire Line
4700 1400 5650 1400
4900 1400 5850 1400
Wire Wire Line
4650 1300 4700 1400
4850 1300 4900 1400
Wire Wire Line
1600 1400 2250 1400
2450 1400 2500 1300
Wire Wire Line
2250 1400 2300 1300
Wire Wire Line
2300 1300 4650 1300
2500 1300 4850 1300
Text Notes 1450 1250 2 50 ~ 0
PHI0r2
Wire Wire Line
4500 1250 5650 1250
4700 1250 5850 1250
Wire Wire Line
1600 1250 2050 1250
2250 1250 2300 1150
Wire Wire Line
2050 1250 2100 1150
4300 850 5850 850
Wire Wire Line
1600 1100 1950 1100
Wire Wire Line
1950 1100 2000 1000
Text Notes 1450 1100 2 50 ~ 0
PHI0r1
Wire Wire Line
4100 850 5650 850
Wire Wire Line
4050 950 4100 850
4250 950 4300 850
Wire Wire Line
3100 1750 4250 1750
Wire Wire Line
4250 1750 4300 1850
Wire Wire Line
2100 1150 4450 1150
2300 1150 4650 1150
Wire Wire Line
4450 1150 4500 1250
Wire Wire Line
4400 1100 5650 1100
Wire Wire Line
4350 1000 4400 1100
Wire Wire Line
2000 1000 4350 1000
4650 1150 4700 1250
Text Notes 5550 1550 0 50 ~ 0
0
Wire Wire Line
@ -818,15 +800,15 @@ Wire Wire Line
Wire Wire Line
5500 1450 5650 1450
Wire Wire Line
5500 550 5500 650
5700 550 5700 650
Wire Wire Line
5500 650 5600 650
5700 650 5800 650
Wire Wire Line
5600 650 5600 550
5800 650 5800 550
Wire Wire Line
5600 550 5650 550
5800 550 5850 550
Wire Wire Line
5400 550 5500 550
5600 550 5700 550
Text Notes 5300 2150 0 50 ~ 0
NOP
Wire Wire Line
@ -1313,7 +1295,7 @@ Wire Wire Line
Wire Wire Line
2500 2600 3050 2600
Wire Wire Line
2400 550 2400 650
2600 550 2600 650
Wire Wire Line
4100 1550 4250 1550
Wire Wire Line
@ -1360,4 +1342,36 @@ Wire Wire Line
2500 2000 5650 2000
Text Notes 1450 1850 2 50 ~ 0
DEVSELr2
Wire Wire Line
2050 1100 2100 1000
Text Notes 1450 1100 2 50 ~ 0
PHI0r1
Wire Wire Line
4500 1100 5750 1100
Wire Wire Line
4450 1000 4500 1100
Wire Wire Line
2100 1000 2150 1000
Wire Wire Line
2100 1100 2150 1000
Wire Wire Line
1600 1100 2050 1100
Connection ~ 2050 1100
Wire Wire Line
2050 1100 2100 1100
Connection ~ 2150 1000
Wire Wire Line
2150 1000 4450 1000
Wire Wire Line
1600 650 1600 550
Wire Wire Line
1700 550 1600 550
Wire Wire Line
1700 650 1700 550
Wire Wire Line
1800 650 1700 650
Wire Wire Line
1600 1250 2250 1250
Wire Wire Line
1600 1400 2450 1400
$EndSCHEMATC

14
cpld/GR8RAM.v
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@ -296,10 +296,6 @@ module GR8RAM(C25M, PHI0, nRES, nRESout, SetFW,
if (IS==6) WRD[7:0] <= { WRD[5:0], MISO, MOSI };
else WRD[7:0] <= RD[7:0];
end 5: begin // NOP CKE
if (AddrLSpecSEL) RDD[7:0] <= Addr[7:0];
else if (AddrMSpecSEL) RDD[7:0] <= Addr[15:8];
else if (AddrHSpecSEL) RDD[7:0] <= { SetEN24bit ? Addr[23:20] : 4'hF, Addr[19:16] };
else RDD[7:0] <= SD[7:0];
end 6: begin // NOP CKE
if (IS==6) WRD[7:0] <= { WRD[5:0], MISO, MOSI };
else WRD[7:0] <= RD[7:0];
@ -324,6 +320,16 @@ module GR8RAM(C25M, PHI0, nRES, nRESout, SetFW,
endcase
end
/* Apple data bus from SDRAM */
always @(negedge C25M) begin
if (PS==5) begin
if (AddrLSpecSEL) RDD[7:0] <= Addr[7:0];
else if (AddrMSpecSEL) RDD[7:0] <= Addr[15:8];
else if (AddrHSpecSEL) RDD[7:0] <= { SetEN24bit ? Addr[23:20] : 4'hF, Addr[19:16] };
else RDD[7:0] <= SD[7:0];
end
end
/* SDRAM command */
output reg RCKE = 1;
output reg nRCS = 1;