Features 80C52 Compatible 8051 Pin and Instruction Compatible Four 8-bit I/O Ports Three 16-bit Timer/Counters 256 Bytes Scratch Pad RAM 9 Interrupt Sources with 4 Priority Levels Dual Data Pointer Variable Length MOVX for Slow RAM/Peripherals ISP (In-system Programming) Using Standard V Power Supply CC Boot ROM Contains Low Level Flash Programming Routines and a Default Serial 8-bit Loader High-speed Architecture Microcontroller In Standard Mode: 40 MHz (Vcc 2.7V to 5.5V, both Internal and external code execution) with 16K/ 60 MHz (Vcc 4.5V to 5.5V and Internal Code execution only) In X2 mode (6 Clocks/machine cycle) 32K Bytes Flash 20 MHz (Vcc 2.7V to 5.5V, both Internal and external code execution) 30 MHz (Vcc 4.5V to 5.5V and Internal Code execution only) 16K/32K Bytes On-chip Flash Program/Data Memory Byte and Page (128 Bytes) Erase and Write AT89C51RB2 100K Write Cycles On-chip 1024 Bytes Expanded RAM (XRAM) Software Selectable Size (0, 256, 512, 768, 1024 Bytes) AT89C51RC2 256 Bytes Selected at Reset for TS87C51RB2/RC2 Compatibility Keyboard Interrupt Interface on Port P1 SPI Interface (Master/Slave Mode) 8-bit Clock Prescaler Improved X2 Mode with Independent Selection for CPU and Each Peripheral Programmable Counter Array 5 Channels High-speed Output Compare/Capture Pulse Width Modulator Watchdog Timer Capabilities Asynchronous Port Reset Full Duplex Enhanced UART Dedicated Baud Rate Generator for UART Low EMI (Inhibit ALE) Hardware Watchdog Timer (One-time Enabled with Reset-out) Power Control Modes Idle Mode Power-down Mode Power-off Flag Power Supply: 2.7 to 3.6 (3V Version) 2.7 to 5.5V (5V Version) Temperature Ranges: Commercial (0 to +70C) and Industrial (-40C to +85C) Packages: PDIL40, PLCC44, VQFP44 Description The AT89C51RB2/RC2 is a high-performance Flash version of the 80C51 8-bit micro- controllers. It contains a 16K or 32K Bytes Flash memory block for program and data. The Flash memory can be programmed either in parallel mode or in serial mode with the ISP capability or with software. The programming voltage is internally generated from the standard VCC pin. Rev. 4180E805110/06The AT89C51RB2/RC2 retains all features of the 80C52 with 256 Bytes of internal RAM, a 9-source 4-level interrupt controller and three timer/counters. In addition, the AT89C51RB2/RC2 has a Programmable Counter Array, an XRAM of 1024 Bytes, a Hardware Watchdog Timer, a Keyboard Interface, an SPI Interface, a more versatile serial channel that facilitates multiprocessor communication (EUART) and a speed improvement mechanism (X2 mode). The Pinout is the standard 40/44 pins of the C52. The fully static design reduces system power consumption of the AT89C51RB2/RC2 by allowing it to bring the clock frequency down to any value, even DC, without loss of data. The AT89C51RB2/RC2 has 2 software-selectable modes of reduced activity and 8-bit clock prescaler for further reduction in power consumption. In Idle mode, the CPU is fro- zen while the peripherals and the interrupt system are still operating. In power-down mode, the RAM is saved and all other functions are inoperative. The added features of the AT89C51RB2/RC2 make it more powerful for applications that need pulse width modulation, high speed I/O and counting capabilities such as alarms, motor control, corded phones, and smart card readers. Table 1. Memory Size TOTAL RAM Part Number Flash (Bytes) XRAM (Bytes) (Bytes) I/O AT89C51RB2 16K 1024 1280 32 AT89C51RC2 32K 1024 1280 32 AT89C51IC2 32K 1024 1280 32 2 AT89C51RB2/RC2 4180E805110/06