These devices can address up to 64 Kbytes of external program/data memory.
The Intel 87C51FA/8XC51FB/8XC51FC is a single-chip control oriented microcontroller which is fabricated on Intels reliable CHMOS III-E technology. The Intel 83C51FA/80C51FA is fabricated on CHMOS III technology. Being a member of the MCSÉ 51 controller family, the 8XC51FA/8XC51FB/8XC51FC uses the same powerful instruction set, has the same architecture, and is pin-for-pin compatible with the existing MCS 51 controller products. The 8XC51FA/8XC51FB/8XC51FC is an enhanced version of the 8XC52/8XC54/8XC58. Its added features make it an even more powerful microcontroller for applications that require Pulse Width Modulation, High Speed I/O and up/down counting capabilities such as motor control.
For the remainder of this document, the 8XC51FA, 8XC51FB, 8XC51FC will be referred to as the 8XC51FX, unless information applies to a specific device.

■ High Performance CHMOS EPROM/ROM/CPU
■ 12/24/33 MHz Operation
■ Three 16-Bit Timer/Counters
■ Programmable Counter Array with:
   - High Speed Output,
   - Compare/Capture,
   - Pulse Width Modulator,
   - Watchdog Timer Capabilities
■ Up/Down Timer/Counter
■ Three Level Program Lock System
■ 8K/16K/32K On-Chip Program Memory
■ 256 Bytes of On-Chip Data RAM
■ Improved Quick Pulse Programming Algorithm
■ Boolean Processor
■ 32 Programmable I/O Lines
■ 7 Interrupt Sources
■ Four Level Interrupt Priority
■ Programmable Serial Channel with:
   - Framing Error Detection
   - Automatic Address Recognition
■ TTL Compatible Logic Levels
■ 64K External Program Memory Space
■ 64K External Data Memory Space
■ MCSÉ 51 Controller Compatible Instruction Set
■ Power Saving Idle and Power Down Modes
■ ONCE (On-Circuit Emulation) Mode
■ Extended Temperature Range Except for 33 MHz Offering (b40§C to a85§C)