8255 parallel interface
8255 is universal and programmable parallel interface (PPI) chip, probably
the most popular that was connected to microprocessors.
There are many ways the device was connected, but some are most popular.
Below is a table that describes these solutions.
Computer
Interface | Ports | Slot | Notes |
Didaktik
build-in | #1F
#3F
#5F
#7F | edge 32 male
4 is key | Slot includes 2 inverters and +5V. |
Elwro 800
Junior
build-in | #DF
#DE
#DD
#DC | #1F
| DB9 male
Amphenol 36 | All 8255 ports are available #DC..#DF, PA also in #1F address (A0 and A1 lines are inverted). PA is joystick input in DB9; PB (data) and PC2 (ack), PC7 (strobe) in Amphenol 36 drive the printer. Other signals not used at all. |
SVI 738
(MSX)
build-in | #A8
#A9
#AA
#AB | DIN 7
(cassette) | Most of signals are for internal use. PA selects memory pages, PB and PC0..PC4 are dedicated to read keyboard. PC4 - cassette motor relay (0=on), PC5 - cassette audio out, PC6 - CAPS-LOCK lamp (0=on), PC7 - keyboard klick bit. |
TC2048
? | #38
#39
#3A
#3B | edge 34 male | Interface used for EPROM simulator. |
UK2086
Centromix
Centronix | #3B
#5B
#DB
#FB | DB15 male | Build-in in some models. Only PB and half PC are available in slot. |
ZX Spectrum
D40 / D80 | #1F
#3F
#5F
#7F
(#91)
(#99) | edge 32, male
4 is key | Slot includes 2 inverters and +5V.
8255 must be activated with OUT #91,#20 (bit 5 - inverted RESET input). Probably because the interface can be connected to Didaktik that has 8255 build-in. Code in ROM checks PC and makes the OUT only when the test fails. The bit 4 in #99 (..#9F?) port can disable (0) and enable (1) access to 8255 ports (not used in ROM). |
ZX Spectrum
MB-02 | #1F
#3F
#5F
#7F | #1B
#3B
#5B
#7B | DB37 female
(DB9 male) | Addresses set is selectable. Slot includes +5V and /RESET. (Kempston Joystick in #1F) |
ZX Spectrum
PB-3 | ? | DB15 male (T)
DB15 female (D) | (Seems to be similar to Centromix in UK2086, with 2 slots this time.) |
ZX Spectrum
UR-4 | #1F
#3F
#5F
#7F | edge 30 male
DB9 male | Slot includes +5V. Kempston Joystick in #1F (inverters via 22kom resistors). |
ZX Spectrum
ZXATASP | #XX9F | 2x20 pins male
Compact Flash | Slot allows the IDE device to be connected directly. PC used also to switch extra memory banks. |
-
YAMOD
EPROG | #30
#31
#32
#33
(#34) | 2x17 pins male
32 pins socket | Socket for 24, 28 or 32 pins EPROM, +5V and Vpp switchable with jumpers. Signals in the 34 pins slot are independent from jumpers. |
-
YAMOD
IDE8255 | #1B
#3B
#5B
#7B | 2x20 pins male | Slot allows the IDE device to be connected directly. MODE 1 can be used for reading. |
-
YAMOD
MB02PIO | #1F
#3F
#5F
#7F | #1B
#3B
#5B
#7B | DB37 female
2x20 pins male | Addresses set is selectable. DB37 slot includes +5V. Can be configured to work as YAMOD.IDE8255. |
Links to other pages
See also
- 8211 8250 8251 8253 8255 8257 8259 8272
- Family of interface chips: 8211, 8250, 8251, 8253, 8255, 8257, 8259, 8272.
- Elwro 800 Junior
- Elwro 800 Junior - ZX Spectrum clone produced in Poland. Also works under CP/M 2.2 (CP/J) with access to disk drive via a network.
- PB-3
- Polbrit PB-3 interface.
- YAMOD.EPROG
- Very simple and cheap EPROM programmer. Based on 8255, can program up to 1MB.
- YABUS.IDE8255
- Quite fast IDE multiplexer made from 8255 PIO.
- Unipolbrit Komputer 2086
- Unipolbrit Komputer 2086. Polish version of Timex Computer 2068.
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