Overview: FUJITSU
11111111111111111111111111111111111111111111111111111111111111111 MB 88304 MB 88305
April 1986 Edition 1.1 NMOS INPUT/OUTPUT EXPANDER
The Fujitsu MB 88304/MB 88305 are peripheral integrated circuits that can be connected to a 4-bit or 8-bit single-chip microputer (MCU) to provide additional I/O ports. Besides furnishing simple I/O port expansion, the MB 88304 and MB 88305 can AND or OR port data with data from the MCU, on instruction from the MCU.
The MB 88304/MB 88305 are pseudo-bidirectional ports. They are accessed in 4-bit units, but each individual bit can be used for either input or output, and input and output can be intermixed. The interface to the MCU requires only the connection of a 4-bit interface port and a strobe signal. All output ports of the MB 88304 are open-drain; MB 88305 output ports all have pull-up resistors. The output ports on both chips are reset to the high-impedance state at power-up.
The MB 88304/MB 88305 are fabricated with N-channel silicon-gate E/D MOS process, and packaged in 24-pin plastic DIP. Also, they are powered with a single +5V power supply, and operate over the ambient temperature range of _30°C to +70°C.
