Commodore 16

The C16 was an eight- bit home computers from Commodore. He was a model of the Commodore 264 series and should replace the VC 20 as an entry computer.


The C16 was built to compete against other computers by Timex Corporation, Mattel, and Texas Instruments in the price range below $ 100. It was intended as a successor to the VIC-20, because this was now technically obsolete. The then successful C64 was not suitable with more RAM and better sound and graphics chips for the lowest price segment. The computer Sinclair ( ZX80/ZX81/Spectrum 16k ) were indeed cheaper than the VC 20, but had not the great typewriter keyboard. Jack Tramiel, founder of Commodore International Ltd.. , Feared that some Japanese companies would try using very inexpensive home computers (MSX ) in the U.S. market to gain a foothold. Thus, the C16 was launched to give Commodore in the lower price segment a strong foothold. Atari offered with the Atari 600XL and a home computer for the lower entry-level market to, the bigger brother, the Atari 800XL, was in competition with the Commodore 64

The C16 was announced in June 1984 and was sold from 1985. At this time, Mattel and TI had withdrawn from the home computer market, while Japanese companies brought then with the MSX computers and home computers on the market, but these were rather in competition with the Commodore 64 in 1984, but were home computers with 64 KB RAM (C64, Atari 800XL, 464 CPC, MSX ), so that one had previously promised no great success to the C16/C116 already as an entry level home computer.

How to complete the 264 - series ( C16, C116 and Plus / 4 ) Trio was not a great success and the C16. So first there was no appreciable amount of games and "real" applications.

Only by the position of "first computer from Aldi " He achieved a certain notoriety in Germany and experienced a small boom. These were originally purely a sales action of remaining stocks. The computer was used together with a Datasettenlaufwerk 1531 and a BASIC course software offered at Aldi as a "learning package BASIC" for only 149 DM. After the complete batch was sold out within a few days and only in the half of the ( then) Federal territory, had made ​​spare parts remnants still copies will be reproduced to satisfy the demand halfway. This small boom also made ​​itself felt in the software market. One of the German software company, which then some then for the time and fairly simple system brought out quality games and applications, Kingsoft was.

Very successful the C16/116 was also in some Eastern Bloc countries without their own home computer industry, especially in Hungary. There were only a few can afford the built in East Germany and the Soviet Union computer, and most Western models were not available. Thither other residues of the C16 and C116, were easy to clear the camp without disposal costs, exported at very reasonable prices, which is its own small boom triggered. From there, a number of unofficial conversions popular C64 games come on the C16.

Commodore has made with the C16/116/PLUS4 as well as later with the Amiga 600 competitors for its own products, but without exceeding the previous performance.

The C16 contains an early example of an Easter Egg: When entering the SYS 52650 command, the name of the developer F. Bowen, J. Cooper, B. stove, T. Ryan will be displayed. F. Bowen appears this inverted T. Ryan flashing. The lead hardware developer Bil Herd was later also responsible for the development of more successful Commodore 128.


Externally similar to the C16 the VC 20 and the C64, but with a black case and light gray keys; the keyboard layout was partially unlike the VIC-20 and C64, so there were now four separate cursor control keys (arrow keys ), while the reset button RESTORE accounted in favor of a side-mounted reset button.

The C16 had other than the C64 not a registered port. The largest port is the expansion port, which also serves the floppy was connected in 1551. On the right side of the case to

  • Power supply (9 V DC, 1 A, inner pole negative, external positive)
  • On / off switch
  • Reset button
  • Two eight-pin mini-DIN connectors for connecting joysticks (see below)

On the back side of the case are:

  • Serial bus port ( CBM - bus to connect the floppy disk drives in 1541, 1570, 1571 or 1581 of the C64 or a serial printer, same socket as the VIC-20 and C64 );
  • A seven- pin mini-DIN socket for connecting the 1531 Datasette ( see below);
  • Audio / Video output (DIN, eight poles, same socket as the C64) to connect a monitor with a composite or S -Video input or a suitably equipped television set;
  • RF output for direct connection of PAL or NTSC televisions via their aerial socket (PAL devices use the UHF channel 36, 591.25 MHz);
  • Expansion port, with a smaller socket than the expansion port of the C64 and also electrically non- compatible with it.


  • CPU: The CPU used in the C16 is an eight -bit or 7501 - MOS MOS 8,501th Despite the different names, the CPUs are identical, only the manufacturing process was changed so that MOS decided to make this known to us through a name change. The 7501 - and 8501 - CPU is in terms of the official instructions, instruction compatible to 6510 CPU of the C64. Due to the radically altered internal structure of the 264 series, in contrast to C64 but hardly from this capital could be beaten. In C16, the CPU handles using its built Ein-/Ausgabe-Port from the control of Datasette and serial bus.
  • Frequency: The C16 operates at 885 kHz and 1.76 MHz. The TED chip generates the clock frequency and switches between these frequencies back and forth, depending on whether he himself also needs access to the bus. So the TED operates at the graphics output and DRAM refresh with the low and on during the presentation of the screen frame and the synchronous pulses on the high frequency. The rate of C16 is thus only about 1 MHz on average.
  • RAM: Sold was the C16 with 16 KB RAM, with only 12,277 bytes in BASIC (approx. 12 KB) were available. When the graphics mode is the free memory for BASIC programs decreased to 2 KB. The maximum intended memory capacity of the C16 is 64 KB, so that by replacing the two μPD4416 DRAM chips (16 KB × 4) against pin-compatible μPD4464 DRAMs (64 KB × 4) and the drawing of two jumpers (which are not increase associated address line both address decoder to the corresponding connector on each RAM chip ) the free BASIC memory 60 671 bytes ( 60 KB) leaves (larger memory expansions, eg 256 KB, can by realized by hobbyists bank switching solutions integrate ). The last models have because of the temporary cessation of production of the 4416 chips at the factory, the 4464 Rams, so you only have to set the jumpers. The C16 is so advanced from software point of view except for the missing ROM application software (3 - plus-1 ), the missing 6551 interface chip for the RS- 232 interface and the Acht-Bit-I/O-Chip MOS 6529 is identical to the Plus / 4, therefore all Plus/4-Software ran out of terminal programs virtually on such a system. Also, some C -16 games could use the additional memory to represent, for example, better graphics.
  • ROM: In the 32 -KB ROM of C16 BASIC 3.5, an advanced BASIC 2.0 of the C64 is. In this ROM is an integrated machine language monitor, with which users can debug programs.
  • TED chip: the ' text editor ' TED chip was manufactured under the name of MOS MOS 7360. While in the C64 for the graphics and sound output as well as the interfacing still different ICs were installed (VIC -II, SID, 2x CIA), the TED was the all-rounder of the C16. The 48 -pin DIL chip takes over the graphic output and generates the composite video signal. It generates the sound, reads the keyboard and joystick inputs, three timers contains (two independent), the clock frequency generated of the C16, containing the memory interface and provides the DRAM refresh cycle. He can address the entire 64 -KB address space of the C16 and produces the necessary to memory access signals (RAS, CAS and MUX). For ROM accesses, it addresses the proper chip select (CS ) lines, depending on the state of the internal registers.
  • Graphics: 320 x 200 with 121 colors. For more details, see TED.
  • Sound: Mono, two votes with four octaves. One of the parts can only produce square waves, rectangular waves or the other noise. Volume can only be adjusted for both total votes in eight steps. Three -bit digital sound is possible. For more details, see TED.
  • Joystick: Commodore decided to deviate from the established de facto standard of the Atari 2600 and held the nine pin D -Sub male connectors to build in eight-pin mini- DIN connectors. Commodore itself sold only one, but poor quality joystick model for this connection, and other companies were no available. The control logic is only slightly different, so that for simple joystick ( like without sustained fire ) were adapter cable available soon. Only joysticks, unlike the C64 are connected to the joystick port of the C16; for paddles, light pens and mice of the connection is not suitable. In contrast to the C64 allows the C16 hardware, keyboard and joystick completely separate and interrogate without mutual interference; the built-in firmware uses this possibility, however, is not sufficient, that also appear at C16 nonsense characters when you move to the BASIC prompt the joystick.
  • Datasettes interface: On this 300 - baud interface a Commodore -1531 - Datasette could be connected. In contrast to the edge connector of the 1530 Datasette all previous Commodore computers had in 1531 a round mini - DIN connector. The signals are, however, identical, so that adapter in both directions have been available soon.
  • Serial Port: The ' Commodore Serial Bus ' was a separate developed by Commodore serial bus. The C16 had the same bus as the CBM - C64, thus the serial printer and floppy drives (1541 ) were the C64 and C16 are operated on, but they were also just as slow.
  • Expansion Port: The C16 could be extended by modules, these were then operated in that slot (but only published very few on the market). The faster Floppy 1551 C16 was also operated via the expansion port. Something was unfortunate, however, that the expansion port was simply looped through the chunky plug of 1551. If several 1551 should be operated first had to plug into each other and are then plugged into the expansion port. As a result, you could not operate the C16 edge of a table, because the connector expansion port mechanically very loaded by its own weight to.

The end of the 264 series

The complete 264 - series had three major problems: they had except for the Plus / 4 not a registered port, the programs were not compatible with the C64 and game programmers had the problem that the TED is no hardware support for sprites possessed as the VIC-II of the C64. Although the in contrast to C64 improved BASIC interpreter also provided graphics capabilities, including shapes; for game programming, which was usually in assembly language, but this was not significant. In addition, the C64 with its SID was a much better sound than produce the TED.

Just the TED often caused frustration because the TED chip had no heatsink, but heated by a continuous operation at high clock frequency is too strong, so that he could burn out. Also plugging or unplugging cables to the joystick ports during operation can be easily burn through the TED, as it is unprotected associated with these.

The CPU in the C16, since it is unprotected connected to the serial port and the Datasettenanschluss also burn when plugging or unplugging cables to these ports during operation. The end of the production of the C16 some protection diodes have been retrofitted in the circuit, to mitigate the problem.

Commodore saw the incompatibilities as not a big problem, because after all, many owners were of a VC- 20 changed for the sequel to C64, although this was not compatible. VC -20 users who had been able to care for the C16, but there were 1985 not many, and C64 -owners already had the worse in most technical characteristics C16 to change no incentive, especially since the publication date of the C16 a huge amount was available to software for the C64 and the C16 not a registered port for extensions had like the C64. Thus, the C16 and the complete 264 series was a flop.