Plus/4

Commodore Plus/4Although The CBM Plus/4 was designed for business and programming it was not successful as it was first thought. This was caused by the fact that it was not expandable as it’s predecessor, and was not compatible with the Commodore 64. Also its built in Software like spreadsheet and database was very limited. Regarding software Commodore released many titles and other software companies released software for both the Plus/4 and C16, but it was never a hit due to its predecessor was still strong and the Amiga was announced later same year.

 
Plus/4
1984 $299(USA) – £190(UK)
Boxed:EA5111058
1984
7501 or 8501 8 BIT CPU working on a frequency of 1.75Mhz and 6502 Compatible. The processor can access 64Kbytes of memory, between Ram and Rom.
64 Kbytes of Rom in which 32 Kbytes are used for the Operating system and basic, and the rest of the 32 Kbytes Contains four Custom programs. 64 Kbytes of Ram expandable to 512 KB.
TED 7360 or TED 8360 with 5 Display modes, a resolution of 320 x 200 and a palette of 15 colours with 8 intensity levels per colour and black, which gives you a total of 121 colours.
TED 7360 or TED 8360 with 2 channel sound, of which one channel capable of producing white noise. Also the Plus/4 has the ability to play digitized sound with an amplitude resolution of 3 bits.
1x TV Connector (RF Modulator that transmits both audio and video).
2x Joystick Ports.
1x Tape interface at 300 baud
1x Serial Port for connecting 1541 Disk Drive and Printers
1x Bus Expansion Port or Cartridge Port User Port.
Same as the Commodore 64 Power supply, with 9v and 5v output the power connector is different only the internals are similar.
Weight & dimensions for the Commodore Plus 4 are 1.34 kg, 335 x 205 x 57 mm (W x L x H).
Not more than 600,000 units in Europe.

The club currently owns two Commodore Plus/4 in excellent working condition. Boxed with two manuals, RF lead and power supply. The second Plus/4 is used for display and for testing peripherals.

 

Cassette

7 Pin MINI-DIN Female
at the Computer
Pin Name Dir Desc
1 GND N/A Ground
2 +5V OUT +5V DC
3 MOTOR OUT Cassette Motor
4 READ IN Cassette Read
5 WRITE OUT Cassette Write
6 SENSE OUT Cassette Sense
7 GND N/A Ground
 

 

Control Port 1

8 Pin MINI-DIN Female
at the Computer
Pin Name Dir Desc
1 JOYA0 IN Joystick UP
2 JOYA1 IN Joystick DOWN
3 JOYA2 IN Joystick LEFT
4 JOYA3 IN Joystick RIGHT
5 +5V OUT DC Supply
6 BUTTON A IN Fire Btn
7 GND N/A Ground
8 COMMON A IN/
OUT		 Data Bit 1
Fire Detect
 

 

Control Port 2

8 Pin MINI-DIN Female
at the Computer
Pin Name Dir Desc
1 JOYB0 IN Joystick UP
2 JOYB1 IN Joystick DOWN
3 JOYB2 IN Joystick LEFT
4 JOYB3 IN Joystick RIGHT
5 +5V OUT DC Supply
6 BUTTON B IN Fire Btn
7 GND N/A Ground
8 COMMON B IN/
OUT		 Data Bit 2
Fire Detect
 

 

Expansion Port

50 Pin Commodore Female
at the Computer
Pin Name Dir Desc
1 GND N/A Ground
2 +5V OUT +5V DC
3 +5V OUT +5V DC
4 /IRQ IN/
OUT		 Request Interrupt
5 R/W IN Read Write 1=Read 0=Write
6 C1 HIGH IN External Cartridge Chip
7 C2 LOW IN External Cartridge Chip
8 C2 HIGH IN External Cartridge Chip
9 /CS1 IN Chip Select Line 1
10 /CS0 IN Chip Select Line 0
11 /CAS IN/ Column Address Strobe
12 MUX IN DRAM addr multiplex
13 BA IN Bus Avail Low=DMA
14 D7 IN/
OUT		 Data Bus 7
15 D6 IN/
OUT		 Data Bus 6
16 D5 IN/
OUT		 Data Bus 5
17 D4 IN/
OUT		 Data Bus 4
18 D3 IN/
OUT		 Data Bus 3
19 D2 IN/
OUT		 Data Bus 2
20 D1 IN/
OUT		 Data Bus 1
21 D0 IN/
OUT		 Data Bus 0
22 AEC IN Address Enable Code
23 EAI IN External Audio In
24 PHI 2 IN/
OUT		 Artificial PHI 2 sig
25 GND N/A Ground
A GND N/A Ground
B C1 LOW IN External Cartridge Chip
C /RESET IN Cold start Reset
D /RAS IN/
OUT		 Row Address Strobe
E PHI 0 IN/
OUT		 Artificial PHI 0 Sig
F A15 OUT Address 15
H A14 OUT Address 14
J A13 OUT Address 13
K A12 OUT Address 12
L A11 OUT Address 11
M A10 OUT Address 10
N A9 OUT Address 9
P A8 OUT Address 8
R A7 OUT Address 7
S A6 OUT Address 6
T A5 OUT Address 5
U A4 OUT Address 4
V A3 OUT Address 3
W A2 OUT Address 2
X A1 OUT Address 1
Y A0 OUT Address 0
Z N/C N/A No Connection
AA N/C N/A No Connection
BB N/C N/A No Connection
CC GND N/A Ground
 

 

Power

4 Pin Commodore Female
at the Computer
Pin Name Dir Desc
1 +5V IN +5V DC
2 9V AC IN 9V AC
3 9V AC IN 9V AC
4 GND N/A Ground
 

 

Serial Port

6 Pin DIN (DIN45322) Female
at the Computer
Pin Name Dir Desc
1 /SRQ IN IN/
OUT		 Serial
SRQIN
2 GND N/A Ground
3 ATN IN/
OUT		 Serial
ATN
4 CLK IN/
OUT		 Serial
Clock
5 DATA IN/
OUT		 Serial
Data
6 /RESET IN Reset
 

 

User Port

24 Port Pin Male Edge
at the Computer
Pin Name Dir Desc
1 GND N/A Ground
2 +5V OUT +5V DC
3 A RESET IN Reset Clock
4 P2 IN/
OUT		 Data 2
5 P3 IN/
OUT		 Data 3
6 P4 IN/
OUT		 Data 4
7 P5 IN/
OUT		 Data 5
8 RxC IN Receive Data
9 ATN IN/
OUT		 Attenuator
10 9V AC OUT 9V AC
11 9V AC OUT 9V AC
12 GND N/A Ground
A GND N/A Ground
B P0 IN/
OUT		 Data 0
C RxD IN Receive Data
D RTS IN Request To Send
E DTR IN/
OUT		 Data Terminal Ready
F P7 IN/
OUT		 Data 7
H DCD IN Data Carrier Detect
J P6 IN/
OUT		 Data 6
K CTS IN/
OUT		 Clear To Send
L DSR OUT Data Set Ready
M TxD OUT Transmit Data
N GND N/A Ground
 

 

Video Port

8 Pin DIN (DIN45326) Female
at the Computer
Pin Name Dir Desc
1 LUM OUT Luminance (Mono) 1V p-p
2 GND N/A Ground
3 AUDIO OUT Audio Imp 1k 2V p-p
4 VIDEO OUT Composite Video 1V p-p
5 AUDIO IN Audio Imp 100k 3V p-p
6 CHROMA OUT Color
7 N/C IN No Connection
8 +5V OUT +5V DC