8355/8755 Multifunction Device (memory+IO)
Features
- 2kbytes ROM(8355) / EPROM(8755)
- Two bidirectional 8 bit I/O ports
- Each port line individually programmable for I or O
- Internal AD demux using ALE
- Generates ready signal
- Separate control lines for I/O section
Block diagram
- Vdd=25V for programming EPROM
- Vcc=5V, Vss=0V
Port and DDR addresses
A1 | A0 | Port/DDR |
0 | 0 | Port A |
0 | 1 | Port B |
1 | 0 | DDR A |
1 | 1 | DDR B |
DDR=Data Direction Register (1=Output, 0=input)