Contents Section Page
Title & Contents (this page) 1Notes & Gate Identification 2Block Diagram 3Timing 4Keyboard and Control (part 1) 5Control (part 2) 6Control (part 3) 7Registers 8Arithmetic 9Decimal Point Management 10Display 11Power Supply 12Timing Diagram 13IC Pinouts 14IC Notes & Gate Construction 15Connectors 16
Commodore DAC-612Calculator
Commodore DAC-612 CalculatorSection: Title and Contents
Page: 1 Rendition: 2014 Mar 7
This schematic has been derived through reverse engineering.This is not the manufacturer’s schematic, nor is it based on the manufacturer’s schematic.
Notes
♦ Gate symbols and signal names are presented in accordance with: logic 0 = GND (0V) logic 1 = V–24
♦ A lowercase “n” in a signal name indicates the logical NOT operation.
♦ The symbol Ncpp denotes a physical connector pin where c=connector, and pp=pin. Solid black end is the male side of the connector. White end is the female side of the connector.
♦ connection between different sections. connection limited to same section. Arrows indicate direction of signal or energy flow.
♦ The symbol denotes V–24.
♦ Resistance in ohms unless otherwise indicated.
♦ Capacitance in microfarads unless otherwise indicated.
♦ These drawings based on unit with Serial No. 209040.
♦ SC1772 ICs of Unit 209040 stamped with 6921 and 6945.
♦ Drawn Jan. to Feb. 2000 by bhilpert. See www.cs.ubc.ca/~hilpert/eec for additional information.
Gate Identification
Gates and logic elements are identified by a symbol of the form:b g n
whereb = board (A, B or C)g = gate type identifier (1 or 2 characters, see table below)n = number
andboard A = lower boardboard B = upper boardboard C = display board
See “Connectors” page for more about board identification.
Gate Type ID Description A discrete AND gateO discrete OR gateS 12–bit shift register in µPD11 ICU 2–input OR gate in µPD101C ICV 3–input OR gate in µPD102C ICY 48–bit shift register in SC1772 IC1D 2 or 3–input OR gate in HD3106 IC1E flip-flop in HD3107 IC1L inverter in µPD13C IC1M serial BCD adder in HD3112 IC1R 48–bit shift register in µPD106 IC2C flip–flop in µPD10(C) IC2D 4–input OR gate in µPD15C IC2E switch in µPD110C IC
See “IC Pinouts and Gate Construction” page for more about the integrated circuits.
Commodore DAC-612 CalculatorSection: Notes
Page: 2 Rendition: 2014 Mar 7
V+170
X
N1
KAC, KC,KADD, KSUB, KMUL, KDIV,KGT, KDP,
KOFF, K54,KENTER
V+90V–24
Z Register(accumulator, 48 bits)
Y Register(2nd operand, 48 bits)
X Register(displayed operand, 48 bits)
Arithmetic7-segment Decoder
and Display
Power SupplyTiming
Y
Z
SUM
Commodore DAC-612 CalculatorSection: Block Diagram
Page: 3 Rendition: 2014 Mar 7
Decimal Point Set-pointRing Counter
Ring Counter
Decimal Point DisplayRing Counter
PD
DP
ØC ØT ØBxbit timing
ØDxdigit timing
PS
PT
Display Latch(4 bits)
N2
N4
N8
KNUM
V–14
Control
AL1 AL2
NEG
Keyboard
ØB8•C
12
131
ØT
ØT
ØB8•CC2C3
D Q
ØC
122
4
ØT10 ØT
ØB8•CC2C3
D Q
ØC
113
ØT
ØD2
ØT
ØB8•CC2C3
D Q
ØC
95
ØD3
ØT
ØB8•CC2C3
D Q
ØC
86
ØD4
ØT
ØB8•CC2C2
D Q
ØC
122
4
ØT 10
ØD5
ØT
ØB8•CC2C2
D Q
ØC
113
ØT
ØD6
ØT
ØB8•CC2C2
D Q
ØC
95
ØT
ØD7
ØT
C2C2
D Q
ØC
86
ØT
ØD8
ØT
C2C1
D Q
ØC
122
4
ØT 10
ØD9
ØT
ØB8•CC2C1
D Q
ØC
113
ØT
ØD10
ØT
ØB8•CC2C1
D Q
ØC
95
ØT
ØT
ØB8•CC2C1
D Q
ØC
86
410C1L1
2.2K
C73522K
5.6K
C735
22K
100
22K
10K3.3
25VINIT
NA23NC8
nINIT
NB3 Na39
ØCNB27 Na285.6K
BN3A495
5.6K
4.7K330pF
2.2K
BN4A495
5.6K
22K
nINIT
ØD11
NC15 NA17
NB14
ØD12
NB16
NA12 NC13
NB15 NC14
NA19
ØB8•C
NC23
ØT
ØCB2C1
D Q
ØC
113
ØT ØT
ØCB2C1
D Q
ØC
95
ØT ØT
ØCB2C1
D Q
ØC
86
Nb20 NA30ØB4
410B1L3
NB31 NC4ØnB8
ØB8
ØB2
ØB1
NB29 NC12
1
2 3BU2BA5
ØB8
ØC
2
Commodore DAC-612 CalculatorSection: Timing
Page: 4 Rendition: 2014 Mar 7
BV1
CA2
AA64ØnD12
ØB8•C
ØnD12•B8•C
Nb16 Na35ØD12•B8•C
10K
BE1C735
5
4 6BU2BA3
ØB8•C
ØD12
ØT
ØB8•CA1E1
D Q
ØC
1314
ØT
5
6 7A1D1
ØD12
INIT
AA25ØD12
ØCØD12•C
NB38 NA4
NC22
311C1L1
ØD0
NC6 NB25
NA28
NC19 Nb8
NA9
68C1L1
ØD1
NC7 NB23
NA31
ØnD1
NC21
NA6
AE1C735
1
1 1
M 1
1
1
1 1 1
1
1
ØB8•C
212C1L1
NC20 NB6
Na38
1
ØnD12 ØnD0
1
13
13
AA37ØnD12
ØCØnD12•C
1
10K
5.6K220pF5.6K 220pF
5.6K
BN2A495
5.6K
4.7K330pFBPC735
BGC735
82K82K
2.2K
BN1A495
5.6K
22K
BE2C735
10K
BE3C735
10K
C735
10K
C735
10K
NN
N N N N N N N N N
ØT
ØT ØT
ØT
Nb3
SXLN (RX1)
AO2KGT
AA46KENTER 2
AA42SR2
SR1 2
SL4 (S6)10K
AE2C735
AA41SnR2
SR1 2
AA612 3
11A1L5 M
13
12 11AU11
113A1L5M
SnL6 (S4,A1)
SL6 (S2)
143
2
A1D1M
INITKAC
6
345
AV2M
SnR2
12
12
13AV2
MKC
212A1L2
SL1 (PD1)
SnL1 (RX2,PD1)M
AA582KENTER
SR2AA29
1ØCØnD12
SMARKEDSR11
AA552
68A1L31
SnL5 (A1,PD1)
SL5 (S1,A2,RX1,PD2)Na21 Nb31
1
2 3AU3M 2
12A1L5M
SnL2 (S6,A1,RY1)Na20 Nb23
4
5 6AU3M
SL3 (S2)AA60
2KMATH
KMATH
KGT
1
2 3BU1MKDP
12
12A1L3
12
11 13B2E2M
2BA4
Nb35 NA32
SnL6
SZCLR (RZ1)
AA402KC
SL4
SnL6
NA33 NB22KC
SnL2
2AA56
KENTER
SL4
Na23 Nb37
1
2 3B2E2M
5
4 6B2E2M
Nb39 Na34
SL8 (PD1)
13
12 11BU5M
SR13SL27 (S1)
SR5
SL12
SL7 (S1,RX2)
AL2
GT
0
1
×
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
+=
–=
2
÷
DP
AC NK20
C
NA36
NK25 Na19
NK23 Na25
NK17 Na31
NK6 Na33
NK19 Na29
NK21 Na27
NK27 NB18
NK1 Nb42
NK2
NK3
NK4
NK14
NK9
NK11
NK13
NK8
NK15
Na9
Nb40
Nb38
Nb36
Nb34
Nb32
Nb30
Nb28
Nb26
Nb24
NB21
Commodore DAC-612 CalculatorSection: Keyboard and Control (part 1)
Page: 5 Rendition: 2014 Mar 7
470K
ØB2
470K
470K
ØB4
ØB8
B2D1
2345
1
ØB1
BA9
BA8
BA7
0
KNUM (RX1)
KAC (S1,PS1)
KC (S3)
KGT (S3)
KSUB (A1)
KDIV (S1)
KDP (S2)
K54 (A1)
5.6K
BA102
OFF5/4CUT
NK12
NK5 Na3KOFF (R1,PS1)
BO1Nb18
KENTER (S4,PS1)NA21
BO4
13579
BO3
2367
BO2
4567
8
9
AO5
AO4
AO6
KAS (S4)
KMD (S4)
KMATH (S3)
5.6K
5.6K
5.6K
5.6K
5.6K
5.6K
5.6K
5.6K
5.6K
AU4
ØT
ØD12•B8•CA2C1
D Q
ØC
122
ØT
410A1L5
ØT
ØD12•B8•CA2C1
D Q
ØC
113
ØT
311A1L3
4
10
MM
M
1
SR1 (S2)
SR2 (S3)
SnR1 (S1)
Na8 Nb25SnR2 (S4,A1)
2
1 3M
AA432
AA442
AO3KGTKDP
KENTERKMATH
Commodore DAC-612 CalculatorSection: Control (part 2)
Page: 6 Rendition: 2014 Mar 7
ØT
ØD12•B8•CA2C1
D Q
ØC
95
ØT2
12
ØT
ØD12•B8•CA2C1
D Q
ØC
86
ØT
B1L3
M
M
M
NA10 NB39SR3 (S1,RY1,PS1)
NA14 NB30SR8 (A1,RX1)
Nb13 Na11SnR3 (S2)
ØT
ØD12•B8•CB2C2
D Q
ØC
122
ØT
ØT
ØD12•B8•CB2C2
D Q
ØC
113
ØT
ØT
ØD12•B8•CB2C2
D Q
ØC
95
ØT
311ØT
ØD12•B8•CB2C2
D Q
ØC
86
ØTA1L2
4
10
M
M
M
M
1
SR4 (DS2)
SRND54 (A1,RX1,RY1)
NB32 NA38
SR7 (S2,A1)
SR5 (S4,A2)
SnR5 (DS1,DT1)
Nb7 NA13
ØT
ØD12•B8•CB2C3
D Q
ØC
122
ØT
ØT
ØD12•B8•CB2C3
D Q
ØC
113
ØT
ØT
ØD12•B8•CB2C3
D Q
ØC
95
ØT
ØT
ØD12•B8•CB2C3
D Q
ØC
86
ØT
4
10
M
M
M
M
SR10 (S2,A1)
SR11 (S3,A1)NB41 Na41
SR12 (S3)
SR9 (DT1)
ØT
ØD12•B8•CB2C4
D Q
ØC
122
ØT
ØT
ØD12•B8•CB2C4
D Q
ØC
113
ØT
ØT
ØD12•B8•CB2C4
D Q
ØC
95
ØT
ØT
ØD12•B8•CB2C4
D Q
ØC
86
ØT
4
10
M
M
M
M
SR13 (S4,R1)
SR16 (S2,A2)
SR14 (S2,A5)
SR15 (S1,A1)
Nb6 NA26
SnL2
12
2131
BV4 MSL24
BA22AL1 2
BA23AnL1
2
410A1L3
5
4 6AU11
1
AA452
SL9
BA36SL17
2
BA312
ØT
ØD12•B8•C A1E1
D Q
ØC
43
ØT
1
A1E1
D Q
ØC
56
ØT
2
7
1 Na18 Nb10
KMD
AA36SL3
1
13
12 11AU4M
AA632SL13
KDIV
10
SL13
KAS
1
2 3B2E4M5
4 6B2E4M
BA32SL12
2
SR5
PL1
1
2 3BU4M
2BA38
SnMARKSnL17
12
13 11BU4M
2BA37SMARK
SnL17
BA21SR13
2
2
1 3BU5M
MBA20SnL2
311B1L2
SL12
M9
10 8BU5SL17
PT
SnL2 M10
9 8BU4
SL10 (A1)
5
4 6BU3M
2BA33
SR12
AA512
KAS
SL4SL6
NA37 Nb11SnL9
SL3
M6
8B1L2
68A1L5
SL9 (S3)M
9 8AU4M
SnL9 (S3)
BA42SL16
2SL11 (S1)
SL16
SL19
AA471
N1N8
ØB8•CØD11
AA53
AA548
10119
AV2M
M
M
ØnD1
SDONEG (A1)
SL5
SL20
SnL2
4
5 6AU4M
SnL2
SL13 (S3,RY1)Na15 NB36
AA592
KMD
SnR1SnL6
AA482
KAS
SnL6SL4
SnR3 212A1L11
SnL22 (RX1,RY1)
SL22 (A1)Na2 NB37
12
13 11BU2M
SZLOAD (A1,RZ1)NB11 Na40BA12
2SR3
SR7
AA492 Na1 Nb1
1
2 3BU3
SL4
KMD10
9 8AU31
AA62
KAS
KMD
AA522
SL4Na5 Nb12SL6
NA8Nb2MSL15 (RY1,DT1)
BA21
ØD12SR5
SnL17
ØC
6
543
BV1BA142
SL17SL27
M
SnR21
13B1L2
212B1L2M
SL12 (S5)
SnL12 (S5,A1)
ØD0
BA172ØC
SMARKSR14
11
12 13B2E5MX
9
8 10B2E5M
PD
BA39
BA40
6
543
BV4M
2
2
SnL12
BA412ØD12•B8•C
SR13
SL13
SnR2
ØT
AS4
D Q12
ØC
27
ØT9
8
M
5
6 4A2E1
8
9 10A2E1M
M
M
3
2 1A2E3
M
ØnD0
Nb4NA22SnMARK (S1)
68A1L2
ØnD12•B8•C
MAA50
ØD1
3 4MSR2
8
91011
BV4M
SL11NA29Nb15SR10
Nb17NA11SMARK (S2)
13
12 11A2E2
12
11 13A2E1
ØC
M
MSMARKED (S1,RY1)
1AA15ØnD0
ØD12
5
4 6BU51BA44
SL12
SR13
2BA43
SR16
M
5
4 6BU4M
SR10 NB5 Na26
Nb19 NA7
SL26 (S1,A2,RY2)
SL25 (PS1)
2BA11
SR7
SnR3
NB35 NA35SL20 (S1,A1,RX1)
B2D1
9121110
13MSR14
SR15SR11
SL21 (A1,RY1)
2BA15
SL12
SR5 Nb33 Na30SL18 (RX2,PD1)
2BA19
SnL12
SR16
NB42 NA42SL19 (S1,RY1,DT1)
M9
10 8BU3SR12
SnL9
12
13 11BU3M
SL14 (A2,RX1,PD1)Nb9 NA16
SR12
SnL9
SL9
SL9SL16 (S2)
SL24
SL24 (S2)
11
12 13B2E3
9
8 10B2E3ØD1
M
M
8119
10
BV31
BA18N8
ØC
BA26SR11
ØD12
M
1212
13
BV3
ØD11
2
SnL17 (S3)
SL17 (S3,A1,R1)
SL26SL7
Commodore DAC-612 CalculatorSection: Control (part 3)
Page: 7 Rendition: 2014 Mar 7
Commodore DAC-612 CalculatorSection: Registers
Page: 8 Rendition: 2014 Mar 7
Nb41
Na42
A2D2
109
1112
13AA11
AA9SUM
68A1L4
BA6KNUM
ØD0ØT
AY1
D Q48
ØC
110
ØT8
7
12
213
1AV1
ØnD12•C
A2D2432
5
1AA12
SUM
68A1L1
410A1L1
ØT
A1R1
D Q48
ØC
94
ØT7
3
Y (A1)
311A1L1
AA8X
SL15
AA101
13A1L2
SnL2 AA13
ØT
AY2
D Q48
ØC
110
ØT8
7
Z (A1)
2
3 1A2E4
113A1L3
2
3 1A2E1
AA14SUM
13
12 11AU2
ØnD12•C 10
9 8AU2
AA26ØD12•C
SUMNb29Na13
X (A1,S1)
AA33
SnL22
SnL22
AA28ØD12•C
SnL1
SnL1
SZCLR
SZLOAD
SXLN
KOFF
ØnD12•C 4
5 6AU2
AA27ØD12•C
ØD12•C
8
10119
BV1SR8 Na24NB20SL7
B2D2
2345
1
SRND54SL20SL14SL5
113B1L3
BA13SRND54
SR3
6
543
BV2NB7 Na22
SL13
SMARKED
SL19
SL21SL26
SL18
AA34SL18
ØD0
AA38
11
13
12SL7 A2E4
8
10
9 A2E4SL26
XYL1 (P1)BA34SL17
SR13 NB40 Na36
M
M
M
M
3
3
1
1
1
1
1
1
1
2
2
11
1
M
M
M
1
3
M
M
1
M
M
2
NC16NB12
N2 (A1,D1)
NB13NC17
68C1L2
NC9NB19N4 (A1,D1)
NA39
NC3NB26
NA41
Commodore DAC-612 CalculatorSection: Arithmetic
Page: 9 Rendition: 2014 Mar 7
ØT
ØC
B1M1
Serial BCD Adder
nA
nQ1
ØC
11
8
ØT
nQ2 14
nQ4 16
nQ8 18
8
9 10B2E1
113B1L1
4
5 6B2E1
N1 (S1,A1,D1)
N8 (S2,A1,D1)10
24
12
1
2 3B2E1ØD12
Øn(DE•B8)
ØnB8 ØnB820
19
5
4 6BU1N1
9
10 8BU1N4
311B1L1
68B1L1nSUM 15
410B1L1
Na32NB28
NC2SUM (RX2,RY1,RZ1)
ØD0BA25
?13
?21BA24
BA1ØC
ØD0
SR14
SR16
nB7
ØB11
2 3B2E5
410A1L4
311A1L4AA24 NB4
Na7
Y
Z
ØD0ØB8•C
SR5
Na16NB10
B2D2
1012
911
13
212B1L1
9
10 8BU2
ØnD12
Na10NB9
ØnD12
11
12 13B2E4ØnD0
BA30
M
M
1
1
1
2
M
M
1
M
M
M
M
M
M
M
M
M
1
2
M
M
M
M
M
11
12 13B2E1ØnD12 M
4
5 6B2E3
M
2
1 3B2E3
5
4 6B2E6
8
9 10B2E6
M(NS)
M
68B1L3
nSUB98
9 10B2E2MØD0
SR8
6
345
BV3SR16
MSR10
BA27SnL12
SR5 2
8
91011
BV2SL26SL14
SR14
nsSL17
SR14 2
ØB1
4
5 6B2E5M
8
9 10B2E4
ØnD0
ØnD12
SR15
SR11
M
SRND54
11
12 13B2E6
2
1 3B2E6M
MM
BA28
BA29M
N2
N8
ØB1ØD0
SR7
SR14
K54
? 174
10B1L2
AL1 (S1)M
MAnL1 (S1)
SZLOAD
SL22
BA16SR14
ØD0 M
12
13 11BU1MKSUB
BA352
SnR2
SL21
SL10
SL5
NB17Na17212A1L4AA35
XØnD12
113A1L4
1
12
12
13BV2
SL26
MSL14
Na14NB8SL5
1
2 3AU21
ØT
ØCB2C1
D Q
ØC
122
ØT
M3
4
10Na37
Nb22
AL2 (S1)
AA57SnL6
11
10 9A1D1M
SnL5
2
1 NC1NA40NEG (D1)
SDONEG NB34NA20
SnL2 AA39
311B1L3M
SL20
M
NC5NB24
Commodore DAC-612 CalculatorSection: Decimal Point Management
Page: 10 Rendition: 2014 Mar 7
A2D1
9121011
13AA18
PS
ØT
AS1
D Q12
ØC
27
ØT9
8
113A1L1
AA20PT
9
10 8AU1
AA31ØD12
MM
AA171
AA19ØD0
2
2
2
AA32
2
ØnD12
1
ØT
ØB8•CA1E1
D Q
ØC
1211
ØT
1 1
Nb14
NA15 NC18DP (PS1,D1)
ØT
AS3
D Q12
ØC
27
ØT9
8
M5
6 4A2E3
9
10 8A2E3
AA4DP
M
1
ØnD12•B8•C
M
12
13 11AU3M
ØT
AS2
D Q12
ØC
27
ØT9
8
M5
6 4A2E2
2
1 3A2E2
AA3PD
M
M
ØnD12•B8•C
M
8
9 10A2E21
M
1
10
ØnD1
8
91110
AV1
ØnD12•B8•C
6
5 4A2E4M
M
ØnD1
3 4M
3 4M
3 4M
Nb21NA3PT (PD1,S1)
NA18PS (PD1,PT1)
Nb27NA5PD (PT2,S1)
SL15
16
131214
A1D1M
INITAA1
KAC 2
SnR5
AO1KOFF
KENTERAA16
2
SR4
AA22
SR4
SnL1
SL1
AA222
ØC
AA232
PD
6
345
AV1
PS
SR3
M
410A1L2
ØB4ØnD12•C
A2D1
5342
1
AA6MØB4
ØnD12•C
AA7M
AA5SL25
M
SR9
AA301
AA211
SL8
ØD12•B8•C
SnL5
SL5
SnR5
12
11 13A2E31ØB1
ØnD0
Nb5NA24PL1 (S1)
SL19
1ØD12•B8•C
2
1 3AU1SL5
SL18
SL14
XYL1
CN20A617
DIGIT 12 (MSD)V+170
56K
V+90
— (negative)
CN4C284
12K
56K
NEG
DIGITS 11 to 1 (LSD)
Digit Transistor11 CN1110 CN129 CN228 CN167 CN136 CN175 CN154 CN143 CN212 CN181 CN19
V+90
5.6K
1
n1
ØD12
12K
3.3K22K
a
d c
fe
b
g p
RODANELFIN
MG–17D
56K
V+90
15K56K
CN3C284
12K
56K
V+90
15K56K
CN6C284
12K
56K
V+90
15K56K
CN8C284
12K
56K
V+90
15K56K
CN5C284
12K
56K
V+90
15K56K
CN9C284
12K
56K
V+90
15K56K
CN7C284
12K
56K
V+90
15K56K
CN1C735
12K
33K
22K
56K
CN10C284
ØT
ØB8•CC2C4
D Q
ØC
122
ØT 113C1L2
2
n2ØT
ØB8•CC2C4
D Q
ØC
113
ØT 212
4
n4ØT
ØB8•CC2C4
D Q
ØC
95
ØT 311
n8
N8
ØT
ØB8•CC2C4
D Q
ØC
86
ØT 410
C1L2
C1L2
C1L2
CN2C284
2.2K
56K
33K
V+90
33K1
13C1L1ØnB8
ØB8
16
1
n1n2
6
5 7
10
11 9
CA4
n1
n4
n2n8
n4
n8
121413
C1D124
n1
1
1
234
2n4
n1
4
1
24
1
C1D1
4
n2
1
N4
N2
N1
DP
4
10
abcdefgp
Commodore DAC-612 CalculatorSection: Display
Page: 11 Rendition: 2014 Mar 7
C1D1
CA9
CA13
CA6
CA12
CA3
CA7
CA8
CA5
CA10
CA11 C1D1
CA1
1
1
1
1
1
1
1
1
1
1
1
1
560
470
680
POWER
5.6K
28VAC
?
3900.5W
100K
V–14
75VAC
black
22160V
22160V
47050V
2SD91
C970
MZ1012
V+170
V+90
0.047
1 AMP. 220V117V100V
240V
red100K
yellow
brown
ZH110
10025V
NA1,2
NB1,2
NC24
NA43,44
NC10
NB43,44
Na43,44
Nb43,44
NK7
V–24
brown
brown
violet
violet
bSn
µPD11
5
10
b1Ln
µPD13C
b2Dn
µPD15C
14
77
black
blue
grey
NC27
NC25
Commodore DAC-612 CalculatorSection: Power Supply
Page: 12 Rendition: 2014 Mar 7
bUn
µPD101C
14
7
bVn
µPD102C
14
7
b1Rn
µPD106
5
10
b2En
µPD110C
7
b1Dn
HD31060D
15
8
b1En
HD31070C
15
8
b2Cn
µPD10C
14
7
bYn
SC1772
6
5
3
B1M1
HD31120D
23
12
22
V–14
3
2
8
1
AS1AS2AS3AS4
A1L1A1L2A1L3A1L4A1L5
B1L1B1L2B1L3
C1L1C1L2
A2D1A2D2
B2D1B2D2
AU1AU2AU3AU4
BU1BU2BU3BU4BU5
AV1AV2
BV1BV2BV3BV4
A1R1 A2E1A2E2A2E3A2E4
B2E1B2E2B2E3B2E4B2E5B2E6
A1D1
C1D1
A1E1A2C1
B2C1B2C2B2C3B2C4
C2C1C2C2C2C3C2C4
AY1AY2
B1M1
28VAC
0µS 901080
Commodore DAC-612 CalculatorSection: Timing Diagram
Page: 13 Rendition: 2014 Mar 7
(44 KHz) ØC
ØT
(11 KHz) ØB1
ØB2
ØB4
ØB8
ØB8•C
(847 Hz) ØD0
ØD1
ØD12
1 1
ØnD12•C
PD
180 270 360 450 540 630 720 810 900 990 108011700µS 90
2 3 4 5 6 7 8 9 10 11 12 1 1
XX and PD with
000987654321.in the display.
One full number cyclein registers
Digit being displayed,also ØDn
Digit in register outputs
1(LSD)
2 3 4 5 6 7 8 9 10 11 12(MSD)
-12 -
logic 1 (V–24)
logic 0 (GND)
ØD12•C
ØnD12•B8•C
ØD12•B8•C
NECµPD10C
id: 2C
–24V
GND
14 13 12 11 10 9 8
1 2 3 4 5 6 7
NECµPD11
id: S
NECµPD13C
id: 1L
GND
14 13 12 11 10 9 8
1 2 3 4 5 6 7
NECµPD15C
id: 2D
14 13 12 11 10 9 8
1 2 3 4 5 6 7
NECµPD101C
id: U
14 13 12 11 10 9 8
1 2 3 4 5 6 7
NECµPD102C
id: V
14 13 12 11 10 9 8
1 2 3 4 5 6 7
NECµPD106
id: 1R
NECµPD110C
id: 2E
14 13 12 11 10 9 8
1 2 3 4 5 6 7
–24V
HITACHIHD3106 0D
id: 1D
HITACHIHD3107 0C
id: 1E
PHILCOSC1772
id: Y
GND
16 15 14 13 12 11 10
1 2 3 4 5 6 7
9
8
16 15 14 13 12 11 10
1 2 3 4 5 6 7
9
8
HITACHIHD3112 0B
id: 1M
24 23 22 21 20 19 18
1 2 3 4 5 6 7
17
8
16 15 14
9 10 11
13
12
- 7 8 9 10 11 12
6 - 5 4 3 2 1
10 9 8 7 6
1 2 3 4 5
10 9 8 7 6
1 2 3 4 5
10 9 8 7 6
1 2 3 4 5
–24V
GND
µPD10:
µPD10:
–24V
GND
–14V
–24V
GND GND
–24V
GND
GND
–24V
GND
GND GND
GND
–24V
GND
–24V
GND
GND
–24V
Commodore DAC-612 CalculatorSection: IC Pinouts
Page: 14 Rendition: 2014 Mar 7
Q48
D ØT ØC48–bit shift register
DØC48–bit shift register
ØTQ48
ØT
ØC –24V Q1Q8A NEGB
?Q2Q4 SUM?ØD12•B8
Q8ØB8?
D QDØCØT
Q12
Q4
Q DØCØTØTØC
D Q Q DØCØTØTØC
Serial BCD Adder
?
12–bit shift register
Q
DØC
ØTQ
DØC
ØTQ
DØC
ØTQ
DØC
ØT
Notes on Integrated Circuits
♦ Based on supply voltage, circuit impedances and logic density, IC technology are presumed to be early MOS.
♦ Outputs are open-collector, except SC1772.
♦ These diagrams presented in accordance with:• Logic FALSE or 0 is considered to be GND.• Logic TRUE or 1 is considered to be –24V.
♦ Some ICs in the µPD family came in two packages: TO-100/101 cans and 14-pin DIPs. The C suffix indicates the DIP package.
♦ Inferred for µPD110C:The 4 elements are not standard logic elements. They appear to be MOS transistors. They function as a bidirectional switch, or as a 2–input OR gate with one input inverted.
switch is closed when logicalcontrol input b is TRUE (–24V) equivalent
Care is taken in the logic design to ensure another “wire-ANDed” output does not feed back through the element to affect the state of the signal driving the non-inverted input.
♦ Inferred for flip-flops:The flip-flops in this logic family appear to be Master/Slave D-type flip-flops with the clocks for the master and slave sections kept separate. This permits a system design where data capture is done in accordance with the requirements of the logic while all outputs are changed synchronously by a single clock signal.
ØC = Capture Input (master section clock) ØT = Toggle Input (slave section clock)
The state of the D input is captured when ØC is TRUE (–24V).The Q output is set in accordance with the captured state when ØT goes TRUE.
♦ Inferred for HD3112:This device appears to be a full-blown Serial BCD Adder, performing serial addition, bit carry, tens carry, correction for digit sums greater than 9, negation, etc.
Commodore DAC-612 CalculatorSection: IC Notes and Gate Construction
Page: 15 Rendition: 2014 Mar 7
a a
b
aa
b
Discrete Gate Construction
Most AND gates are constructed from discrete diodes and resistors. Most OR gates and complex logic elements are contained in integrated circuits. The internal construction of discrete gates is shown in the following diagrams. A wire-AND or wire-OR construction is indicated by the input line traversing the width of the gate.
All gate outputs ,except the few discrete OR gates and the Philco SC1772 shift registers, require external load resistors (R) connected from the output to V–24. To reduce clutter these resistors are indicated in the schematic by one of the following symbols near the output.
Discrete Modular 30K
100K220K
All discrete OR gates are loaded by a 5.6K resistor to ground.
R
bAn
R
5.6K
bOn
12
3M
r r
N
A B CGND 1 2 GND GND 1 2 GND V+170 27
PT 3 4 ØB1 ØT 3 4 a7 26 –PD 5 6 ØnD1 SL26 5 6 ØnD12 V+90 25
SL25 7 8 SL15 a22 7 8 a14 24 GNDØnD0 9 10 SR3 a10 9 10 a16 ØT 23
SMARK 11 12 ØD12 SZLOAD 11 12 N1 22 (ØB1)SR4 13 14 SR8 N4 13 14 ØD11 ØnD1 21
DP 15 16 SL14 ØB8c 15 16 ØD12 20 ØnD12ØD11 17 18 (PS) a17 17 18 KDP ØnD0 19
ØB8•C 19 20 B34 nN4 19 20 a24 18 DPKENTER 21 22 SnMARK KSUB 21 22 A33 N4 17
INIT 23 24 PL1 ØD1 23 24 N2 16 N1– 25 26 SR9 ØD0 25 26 N8 ØD11 15– 27 28 ØD0 Ø C 27 28 SUM 14 ØB8•C
b15 29 30 ØB4 ØB8 29 30 SR8 ØD12 13ØD1 31 32 SL8 ØnB8 31 32 SR5 12 ØB8B22 33 34 – – 33 34 A20 – 11
SL20 35 36 KAC SL20 35 36 SL13 10 V–24 Kb11 37 38 SR5 SL22 37 38 ØB1 nN4 9 KDP 27N1 39 40 NEG SR3 39 40 XYL1 8 INIT 26 –N8 41 42 SL19 SR11 41 42 SL19 ØD1 7 KC 25
V–14 43 44 V–14 V–14 43 44 V–14 6 ØD0 24 –a b N2 5 KGT 23
b1 1 2 SL22 a1 1 2 SL15 4 ØnB8 22 –KOFF 3 4 – K54 3 4 SnMARK N8 3 KDIV 21SL16 5 6 – PL1 5 6 SR9 2 (SUM) 20 KAC
B4 7 8 SnR2 SR4 7 8 ØnD0 NEG 1 KMUL 19KDP 9 10 B9 SL14 9 10 a18 18 –
SnR3 11 12 – A37 11 12 SL16 KADD 17X 13 14 B8 SnR3 13 14 (DP) 16 –
SL13 15 16 B10 A29 15 16 ØD12•B8•C K9 15B17 17 18 b10 SMARK 17 18 KENTER 14 K4KC 19 20 SnL2 SL25 19 20 ØB4 K7 13
SL5 21 22 B7 PT 21 22 a37 12 K54SXLN 23 24 B20 SnL2 23 24 K9 K6 11
KGT 25 26 SL26 SnR2 25 26 K8 10 –KDIV 27 28 Ø C PD 27 28 K7 K5 9
KMUL 29 30 SL18 X 29 30 K6 8 K8KADD 31 32 SUM SL5 31 32 K5 V–24 7KSUB 33 34 SL7 SL18 33 34 K4 6 KSUB
ØD12•B8•C 35 36 XYL1 SL8 35 36 K3 KOFF 5b22 37 38 ØnD12 SXLN 37 38 K2 4 K3ØT 39 40 SZLOAD SL7 39 40 K1 K2 3
SR11 41 42 b41 a42 41 42 K0 2 K1V–24 43 44 V–24 V–24 43 44 V–24 K0 1
Notes:♦ Italicised expressions are connections with no signal name in the schematic.♦ Bold-faced expressions are signal sources.
Commodore DAC-612 CalculatorSection: Connectors
Page: 16 Rendition: 2014 Mar 7
Component Side
NB2
NB1 NB43
NB44 Nb2
Nb1 Nb43
Nb44
Board B (upper board)
Component Side
NA2
NA1 NA43
NA44 Na2
Na1 Na43
Na44
Board A (lower board)
12H-21 B
12H-21 A
board identifiers,note “A” and “B”