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1989-07-06
|
15KB
|
365 lines
This is my corrected and modified version of Michael W. Fellinger's
1 meg memory. I have made his signal names clearer (* symbols)
and added some modifications:
NOTE 1---This one will speed access time of the memory. It is
It is possible because XRDY (DTACK*) can be asserted
90ns prior to valid data. (Reference: Moterola 68000
data pamphlet). Part of D4 has been deleted because
DTACK* and XRDY are essentially the same signal.
NOTE 2---This change was essential to my Amiga. My Amiga will
not allow wait states because of a refresh operation.
I don't know if this will happen on all Amiga's but
this mod is good any way because it syncs refresh with
the trailing edge of AS*. This keeps the refresh
cycle from interferring with the Memory cycle thereby
speeding memory access. (The symptoms I had before I
added this mod were: The memory test program passed
with no problems but whenever I told the Op system about
it and tried to use it I got a GURU (buss error))
All the mods use parts that are already on the board so all that is
requied is a few wiring changes to implement. If you have any
questions or suggestions please leave me EMAIL and I'll help all I
can. This version works, its working now. I have not built the clock
yet because I'm waiting for my chip. But I have looked over the
schematics and it looks good all execpt the power supply, it looks a
little strange. I have built battery backed-up clocks before and I never
did that. If anybody knows what he is trying to do or has a suggestion
I would appreciate it.
Mike M.
71555,536
-------------------------------------------------------------------------
GND [ 1][ 2][ 3][ 4][13][25][37][49][61][73][85]
5V [ 5][ 6]
A20 1 +-------+ 15 E 1 +-------+ 3
[56]-------+ |O---- [50]-----+> +----
A21 2 | | 14 2 | 1/2 | 4
[58]-------+ |O---- RFR -----+ 74LS +----
A22 3 | | 13 | 393 | 5
[57]-------+ |O---- 1/6 | +---- RFT
| | 12 74LS04 | [B2] | 6
| 74LS |O---- | +--+
| 138 | 11 1 |\ 2 +-------+ |
| |O---- ADR* ----| >O---- ADR +---------+
6 | [A1] | 10 |/ +---+ +--------- 5V
5V ----+ |O---- | O 4
A23 5 | | 9 [B3] |2 +-------+ 5
[59]------O| |O---- SEL* +--+ 1/2 +---- RFRQ
4 | | 7 | 74LS |
GND ----O| |O---- | 74 |
+-------+ AS* 3 | | 6
[74]--+----+> [B4] |O----
5 | +-------+
ADR------+ | O 1
4 +--- | 2/6 +-------- RFR*
AS-------+ \ 6 | 74LS04
2 | |O---+----------------MCYC* | 5 |\ 6
RFC*-----+ / | 1/3 74LS10 +----| >O---- AS
1 +--- | |/
PRCH*----+ | 3,4 +---
74LS20 +-----+ \ 6 13 |\ 12
[A2] 5 | |O---- MRAS --------| >O---- MRAS*
13 +-----+ / |/
RFRQ-----+ | +---
12 +--- | [B3]
ADR*-----+ \ 8 | [A4]
10 | |O---+---------------RFRQ* +---- 5V
AS-------+ / O 4
9 +--- 2 +-------+ 5
RFC*-----+ MRAS---+ 1/2 +---- MUX
| 74LS |
| 74 |
11 3 | | 6
RFD------+--- CDAC*---+> [A3] |O---
10 | \ 8 4 +-------+ 2 +-------+
MRAS*----+ |O-------+ +----- RFC* O 1
9 | / | | 3 AS-----+
HOLD*----+--- | |O----
5 | | 7 +----5V
RFC* ----+ 74SL +----- RFRAS* O 10
| 175 | 6 12 +-------+ 10
| |O---- MUX----+ 1/2 +---- CAST
12 | [A5] | 10 | 74LS |
RFRAS* -----+ +----- PRCH* | 74 |
| | 11 CDAC 11| | 9
| |O---- [15]+--+> [B4] |O---
13 | | 15 | +-------+
CAST -------+ +----- | O 13
9 | | 14 | +----AS
CDAC* ------+> |O---- HOLD* |
+-------+ | 3 |\ 4
O 1 +----| >O----CDAC*
1/4 74LS00 +----5V |/
1 +--- [B3]
ADR ----+ \ 3
2 |[B5] |O---- RCYC
RFC* ---+ / {NOTE 2}
+--- +----5V
O 10
1/4 74125 [D4] 12 +-------+ 10
2 |\ 3 RFT ----+ 1/2 +---- RFD
CAST -----| >-------[18] XRDY | 74LS |
|/O | 74 |
{NOTE 1} 1| 11 | | 9
| AS ----+> [A3] +O---
+--- ADR* +-------+
2/6 74LS04 [B3] 0 13
11|\ 10 9 |\ 8 +----RFR*
UDS* [72]------| >O------ UDS LDS* [70]-------| >O------- LDS
|/ |/
3 11
CAST ------+--- 2/3 74LS10 CAST ------+---
4 | \ 6 10 | \
UDS -------+[B1] |O----- UCAS* LDS -------+[B1] |O----- LCAS*
5 | / 9 | /
MCYC ------+--- MCYC ------+---
13
12,13 |\ 11 10 +--- 5V----+---
A19 [54]---+---| >O--------+ \ 8 2 | \ 12
| |/ 9 | |O----------+[A4] |O----- RAS1*
| RFR* ---+ / 1 | /
| +--- RAST ---+---
|
| 3/4 74LS00 [B5]
| 13
| 4 +--- 5V----+---
+---------------+ \ 6 2 | \ 12
5 | |O----------+[B1] |O----- RAS0*
RFR*----+ / 1 | /
+--- RAST ---+---
12,13|\ 11 10 +---
MCYC*-------| >O-------- MCYC MRAS* ----+ \ 8
|/ 9 | |0---- RAST
4/4 74LS00 [B6] RFRAS* ---+ /
+---
1 +---
RFRQ* -----+ \ 3 RFR 4 +---
2 | |O-----+-------+ \ 6
RFRAS* ----+ / | 5 | |O------ RFR*
+--- +-------+ /
+---
13 +-------+ 11
RFR--------O|> +-------- RA0
| 1/2 | 10
| 74LS +-------- RA1
| 393 | 9
| +-------- RA2
12 | [B2] | 8
+------+ +---+---- RA3
| +-------+ |
GND |
+----------------+
|
| 1 +-------+ 3
+---O|> +-------- RA4
| 1/2 | 4
| 74LS +-------- RA5
| 393 | 5
| +-------- RA6
2 | [C6] | 6
+------+ +---+---- RA7
| +-------+ |
GND |
+----------------+
|
|13 +-------+ 11
+---O|> +-------- RA8
| 1/2 | 10
| 74LS +--------
| 393 | 9
| +--------
12 | [C6] | 8
+------+ +--------
| +-------+
GND
A10 6 +-------+ 7
[34]--------+ +------------- MA0
A1 5 | 74LS | 15
[29]--------+ 153 |O----+
4 | or | 1 |
RA0 ---+----+ 74LS |O----+
| 3 | 253 | |
+----+ | GND
A11 10 | [C1] | 9
[36]--------+ +------------- MA1
A2 11 | |
[27]--------+ |
12 | | 2
RA1 ---+----+ +-------- RCYC
| 13 | | 14
+----+ +-------- MUX
+-------+
A12 6 +-------+ 7
[38]--------+ +------------- MA2
A3 5 | 74LS | 15
[26]--------+ 153 |O----+
4 | or | 1 |
RA2 ----+---+ 74LS |O----+
| 3 | 253 | |
+---+ | GND
A13 10 | [C2] | 9
[39]--------+ +------------- MA3
A4 11 | |
[24]--------+ |
12 | | 2
RA3 ---+----+ +-------- RCYC
| 13 | | 14
+----+ +-------- MUX
+-------+
A14 6 +-------+ 7
[41]--------+ +------------- MA4
A5 5 | 74LS | 15
[21]--------+ 153 |O----+
4 | or | 1 |
RA4 ---+----+ 74LS |O----+
| 3 | 253 | |
+----+ | GND
A15 10 | [C3] | 9
[43]--------+ +------------- MA5
A6 11 | |
[23]--------+ |
12 | | 2
RA5 ---+----+ +-------- RCYC
| 13 | | 14
+----+ +-------- MUX
+-------+
A16 6 +-------+ 7
[45]--------+ +------------- MA6
A7 5 | 74LS | 15
[28]--------+ 153 |O----+
4 | or | 1 |
RA6 ---+----+ 74LS |O----+
| 3 | 253 | |
+----+ | GND
A17 10 | [C4] | 9
[47]--------+ +------------- MA7
A8 11 | |
[30]--------+ |
12 | | 2
RA7 ---+----+ +-------- RCYC
| 13 | | 14
+----+ +-------- MUX
+-------+
A18 6 +-------+ 7
[52]--------+ +------------- MA8
A9 5 | 74LS | 15
[32]--------+ 153 |O----+
4 | or | 1 |
RA8 ---+----+ 74LS |O----+
| 3 | 253 | |
+----+ | GND
10 | [C5] | 9
+--------+ +------------- MA9
| 11 | |
+--------+ |
| 12 | | 2
+--------+ +-------- RCYC
| 13 | | 14
+--------+ +-------- MUX
| +-------+
GND
2 +-------+ 18
MA0 --------+ +-------- p5 all memory chips
17 | 74HC | 3
MA1 --------+ 244 +-------- p7 all memory chips
4 | or | 16
MA2 --------+ Am +-------- p6 all memory chips
15 | 2966 | 5
MA3 --------+ +-------- p12 all memory chips
6 | | 14
MA4 --------+ +-------- p11 all memory chips
13 | | 7
MA5 --------+ +-------- p10 all memory chips
8 | [D3] | 12
MA6 --------+ +-------- p13 all memory chips
11 | | 9
MA7 --------+ +-------- p9 all memory chips
| | 1
| |O---+
| | 19 |
| |O---+
+-------+ |
GND
2 +-------+ 18
MA8 ---------+ +-------- p1 all memory chips
17 | 74HC | 3
UCAS*--------+ 244 +-------- p15 of cols 1-4
4 | or | 16
LCAS*--------+ Am +-------- p15 of cols 5-8
15 | 2966 | 5
RAS0*--------+ +-------- p4 of cols 1,3,5,7
6 | | 14
RAS1*--------+ +-------- p4 of cols 2,4,6,8
R/W 13 | | 7
[68]---------+ +-------- BRW and p3 of all memory chips
8 | [D5] | 12
+----+ +---
| 11 | | 9
+----+ +---
| | | 1
GND | |O----+
| | 19 |
| |O----+
+-------+ |
GND
D15 18 +-------+ 2
[63]---------+ +-------- p2,p14 of E1,E2
D14 17 | 74LS | 3
[65]---------+ 245 +-------- p2,p14 of F1,F2
D13 16 | | 4
[67]---------+ +-------- p2,p14 of G1,G2
D12 15 | | 5
[69]---------+ +-------- p2,p14 of H1,H2
D11 14 | | 6
[71]---------+ +-------- p2,p14 of E3,E4
D10 13 | | 7
[76]---------+ +-------- p2,p14 of F3,F4
D9 12 | | 8
[78]---------+ +-------- p2,p14 of G3,G4
D8 11 | | 9
[80]---------+ +-------- p2,p14 of H3,H4
| [D1] |
19 | | 1
ADR* -------O| +-------- BRW
+-------+
D7 18 +-------+ 2
[82]---------+ +-------- p2,p14 of E5,E6
D6 17 | | 3
[84]---------+ 74LS +-------- p2,p14 of F5,F6
D5 16 | 245 | 4
[86]---------+ +-------- p2,p14 of G5,G6
D4 15 | | 5
[83]---------+ +-------- p2,p14 of H5,H6
D3 14 | | 6
[81]---------+ +-------- p2,p14 of E7,E8
D2 13 | | 7
[79]---------+ +-------- p2,p14 of F7,F8
D1 12 | [D7] | 8
[77]---------+ +-------- p2,p14 of G7,G8
D0 11 | | 9
[75]---------+ +-------- p2,p14 of H7,H8
| |
19 | | 1
ADR* -------O| +-------- BRW
+-------+
