Microchip, 8bit 80C51, Microcontrollers Microcontroller, 20MHz, 8 kB Flash, 44-Pin PLCC

The Microchip AT89C51AC2 8-bit single chip microcontroller is a high performance Flash version of the 80C51 that contains a 32 KB Flash memory block for program and data. It operates on 3V to 5.5V power supply. The 32 KB Flash memory can be programmed either in parallel mode or in serial mode with the ISP capability or with software. It has two software-selectable modes of reduced activity and an 8-bit clock prescaler for further reduction in power consumption. In the idle mode the CPU is frozen while the peripherals and the interrupt system are still operating. In the Power-down mode the RAM is saved and all other functions are inoperative. The microcontroller retains all features of the 80C51 with 256 bytes of internal RAM, a 7-source 4-level interrupt controller and three timer/counters. In addition, it has a 10-bit A/D converter, a 2 KB Boot Flash memory, 2 KB EEPROM for data, a Programmable Counter Array, an XRAM of 1024 bytes, a Hardware WatchDog Timer, and a more versatile serial channel that facilitates multiprocessor communication (EUART). The fully static design reduces system power consumption by bringing the clock frequency down to any value, even DC, without loss of data.

256 Bytes of On-chip RAM
1 KB of On-chip XRAM
32 KB of On-chip Flash Memory
2 KB of On-chip Flash for Bootloader
2 KB of On-chip EEPROM
14-sources 4-level Interrupts
Three 16-bit Timers/Counters
Full Duplex UART Compatible 80C51
Maximum Crystal Frequency 40 MHz, in X2 Mode, 20 MHz (CPU Core, 20 MHz)
Double Data Pointer
21-bit Watchdog Timer (7 Programmable Bits)
10-bit Resolution Analog to Digital Converter (ADC) with 8 Multiplexed Inputs
Package type of VQFP44, PLCC44