MEMORY ORGANIZATION

PROGRAM MEMORY: Up to 4 Kbytes of the program memory can reside on-chip (except 80C31BH). In addition the device can address up to 64K of program memory external to the chip.

DATA MEMORY: This microcontroller has a 128 x 8 on-chip RAM. In addition it can address up to 64 Kbytes of external data memory.

The Intel 87C51/80C51BH/80C31BH is a single-chip control-oriented microcontroller which is fabricated on Intel’s reliable CHMOS III-E technology. Being a member of the MCSé 51 controller family, the 87C51/80C51BH/80C31BH uses the same powerful instruction set, has the same architecture, and is pin-forpin compatible with the existing MCS 51 controller family of products.

■ High Performance CHMOS EPROM

■ 24 MHz Operation

■ Improved Quick-Pulse Programming Algorithm

■ 3-Level Program Memory Lock

■ Boolean Processor

■ 128-Byte Data RAM

■ 32 Programmable I/O Lines

■ Two 16-Bit Timer/Counters

■ Extended Temperature Range (b40§C to a85§C)

■ 5 Interrupt Sources

■ Programmable Serial Port

■ TTL- and CMOS-Compatible Logic Levels

■ 64K External Program Memory Space

■ 64K External Data Memory Space

■ ONCE Mode Facilitates System Testing

■ Power Control Modes

— Idle

— Power Down