Intel 80386 - Page 269

DRAM PAL DESCRIPTIONS
I ======================================================= \ 1
1
state PRECHARGE1 = 1110 ; fi rst precharge after access 1 1
1 IRASO:=
OFF ;both RAS's idle 1 1
1 IRAS1:=
OFF 1 1
1
A2REG:= A2REG ;maintain state of interleave A21 1
1
MUXOE: = MUXOE + RFRQ ; samp 1 e refresh request 1 1
\===================================================== ==1 1
1 1
alwaysl (STARTACCESS * « A2 * A2REG) 1
v +(/A2 * IA2REG))) 1
1= = = ==== ===== ====== = = === ============ ================== == \ 1
1
state PRECHARGE2 = 1111 ; second precharge after access 1 1
1 IRASO:= IA2 * IA2REG * STARTACCESS;start next... 1 1
1 IRAS1:=
A2 * A2REG * STARTACCESS;interleave accesl---------+ 1
1
A2REG: = A2REG ; ma i nta instate of i nterl eave A21 1
1 MUXOE:= MUXOE ;maintain MUXOE state 1 1
\===================================================== ==1 1
I(STARTACCESS * « A2 * A2REG) 1 1
+{/A2 * IA2REG)))+-----------------------------------+
Finally, the karnaugh maps
for the fo 11 owi ng signals
are:
ROWSEl \QO
Q1 \ClK 00 01
11 10
\
MUXOE
00 1 MUX MUX key:
01 1
MUX
MUX
M+R MUX = MUXOE
111
MUX MUX
M+R
M+R = MUXOE + RFRQ
10 1
MUX
MUX
RFR RFR = RFRQ
RO,'SEl \QO
Q1 \ClK 00 01
11 10
\
A2REG
00 1
A2R A2R key:
01 1 A2R A2R
IA2R
A2; = A2
111
A2R A2R A2R A2R = A2REG
10 1
A2R A2; A2;
ROWSEl \QO
Q1 \ClK 00 01
11 10
\
RAS signal s
00 1
lAM AM
lAM AM
key: [RASO:RAS1]
01 1
ON ON lAM AM lAM AM AM = A2REG + MUXOE
111
IAI AI IAI AI OFFOFF AS = A2 * STARTACCESS
10 1
lAM AM lAS AS OFFOFF
AI = A2 * STARTACCESS * i nterl eave
ROWSEl \QO
Q1 \ClK 00
01 11
10
\
ROWSEl state circled
00 1
0010 0111 key:
[ROWSEl: Q1: QO: ClK]
01 1
1000 0110
1101
M = MUXOE * RFRQ
111
1 i i 0
10iO
1111
S = STARTACCESS
10 1
0001 10s0 mMm1 I = STARTACCESS * i nterl eave
ROWSEl \QO
Q1 \ClK 00 01 11 10
\
Q1 state circled
00 1
0010
0111
01 1
1000 0110
1101
111
1iiO lOiO
1111
10 1
0001
10s0 mMml
ROWSEl \QO
Q1 \ClK 00 01 11 10
\
QO state ci rcl ed
00 1
0010
0111
01 1
1000 0110
1101
111
1 i iO 10iO 1111
10 1
0001 10s0 mMml
Figure C-2. 3-ClK DRAM State PAL Equations (Cont'd.)
C-7