1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
| # Kempston Micro Electronics
This article has multiple issues. Please help [improve it](/Special:EditPage/Kempston_Micro_Electronics) or discuss these issues on the [talk page](/Talk:Kempston_Micro_Electronics). ([Learn how and when to remove these messages](/Help:Maintenance_template_removal))
- This article possibly contains [original research](/Wikipedia:No_original_research). Please improve it by [verifying](/Wikipedia:Verifiability) the claims made and adding [inline citations](/Wikipedia:Citing_sources). Statements consisting only of original research should be removed. (February 2010) ([Learn how and when to remove this message](/Help:Maintenance_template_removal))
- This article needs additional citations for [verification](/Wikipedia:Verifiability). Please help [improve this article](/Special:EditPage/Kempston_Micro_Electronics) by [adding citations to reliable sources](/Help:Referencing_for_beginners). Unsourced material may be challenged and removed. Find sources: "Kempston Micro Electronics" – news · newspapers · books · scholar · JSTOR (December 2009) ([Learn how and when to remove this message](/Help:Maintenance_template_removal))
**Kempston Micro Electronics** was a British electronics company based in [Kempston](/Kempston), [Bedfordshire](/Bedfordshire), [England](/England), specializing in computer [joysticks](/Joystick) and related [home computer](/Home_computer) peripherals during the 1980s. Founded on **28 January 1983**, the company became a key player in the [ZX Spectrum](/ZX_Spectrum) accessory market before ceasing operations on **17 December 1993**.
## Company Overview
### Founding and Operations
Kempston Micro Electronics operated as a [limited company](/Limited_company) within the [computing](/Computing) and [electronics](/Electronics) industry. Its primary focus was developing peripherals for the [ZX Spectrum](/ZX_Spectrum), one of the most popular home computers of the era. The company’s most notable product, the **Kempston Interface**, became a de facto standard for joystick connectivity on the Spectrum, allowing users to connect [Atari-standard](/Atari_joystick_port) joysticks to their machines.
### Legacy and Influence
Despite its relatively short existence, Kempston Micro Electronics left a lasting impact on the [home computer](/Home_computer) peripherals market. Its products were widely adopted by gamers and developers, with many [ZX Spectrum](/ZX_Spectrum) games explicitly supporting the Kempston standard. The company’s innovations helped shape the way input devices were integrated into early home computing systems.
## Kempston Interface
### Technical Specifications
The **Kempston Interface** was a [peripheral](/Peripheral) designed to connect joysticks using the [Atari joystick port](/Atari_joystick_port) standard (via a [DE-9 connector](/DE-9_connector)) to the [ZX Spectrum](/ZX_Spectrum). The interface plugged into the computer’s rear expansion port and provided a single joystick port on the front or top of the unit.
### Software Compatibility
Unlike other joystick interfaces of the time, the Kempston Interface did not simulate keypresses. Instead, it delivered joystick state data directly to the [Z80 bus](/Z80) at **port 31**, which could be read in [BASIC](/BASIC) using the command `IN 31`. This method was more efficient and became widely adopted by game developers, making the Kempston standard one of the most supported on the [ZX Spectrum](/ZX_Spectrum).
### Competition and Market Dominance
During the era of the **48K Spectrum**, the Kempston Interface emerged as the dominant standard, outperforming competitors such as:
- **Protek and AGF’s cursor-based solutions**
- **The Fuller standard**
When [Amstrad](/Amstrad) released the [ZX Spectrum +2](/ZX_Spectrum_%2B2), it included a built-in joystick interface compatible with Sinclair’s [ZX Interface 2](/ZX_Interface_2) standard. However, the bundled **SJS-1 joystick** was electrically incompatible with the [Atari standard](/Atari_joystick_port), limiting its usability with existing Kempston-compatible peripherals.
### Safety Considerations
Users were advised against inserting or removing the Kempston Interface while the computer was powered on, as doing so risked damaging the hardware. This precaution was common among [ZX Spectrum](/ZX_Spectrum) peripherals due to the sensitive nature of the expansion port.
## Mouse Interface
Kempston also developed a **mouse interface** for the [ZX Spectrum](/ZX_Spectrum), which mapped cursor movements to specific ports:
- **X-axis**: Port **64479**
- **Y-axis**: Port **65503**
- **Buttons**: Port **64223**
This interface allowed for more precise input than joysticks, though it was less commonly used in gaming applications.
## Joystick Models
### Competition Pro (First Version)
The **Competition Pro** was one of Kempston’s most iconic joystick models, featuring:
- A **square base** for stability
- **Two large red fire buttons** (suitable for left or right-handed use)
- A **black pommel stick** for precise control
- Compatibility with the [Atari 2600](/Atari_2600) standard [DE-9 connector](/D-subminiature)
Originally designed for the [ZX Spectrum](/ZX_Spectrum), the Competition Pro also worked with other home computers, including:
- [Amstrad CPC](/Amstrad_CPC)
- [Commodore 64](/Commodore_64)
- [VIC-20](/VIC-20)
- Later models like the [Amiga](/Amiga) and [Atari ST](/Atari_ST)
An [Atari 5200](/Atari_5200) variant utilized the **CX52 controller** for additional keypad functionality.
### Other Models
- **Formula 1**: Based on the **Quickshot 1**, released in **June 1985**.
- **Score Board**: Featured a base similar in size to a **48K Spectrum**, with **two fire buttons**, also released in **June 1985**.
|