The Atmel AT89 series is an Intel 8051-compatible family of 8-bit microcontrollers (μCs) that were manufactured by the Atmel Corporation. Microchip Technology purchased Atmel in April 2016 and manufactures the AT89 series.

Based on the Intel 8051 core, the AT89 series remains very popular as general purpose microcontrollers, due to their industry standard instruction set, their low unit cost, and the availability of these chips in DIL (DIP) packages. This allows a great amount of legacy code to be reused without modification in new applications. While less powerful than the newer AT90 series of AVR RISC microcontrollers, new product development has continued with the AT89 series for the aforementioned advantages.

More recently, the AT89 series has been augmented with 8051-cored special function microcontrollers, specifically in the areas of USB, I²C (two wire interface), SPI and CAN bus controllers, MP3 decoders and hardware PWM.

Atmel has also created an LP (low power) series of these chips with a "Single Cycle Core", making the execution speed of these chips considerably faster.

AT89 Series Microcontrollers

Device name Flash RAM/XRAMEEPROM max. FrequencyVCCPinsPackagesNotesPublish AT80C51RD2 64KB 1024B -none-40MHz3-5V40, 44PDIP, TQFP, PLCCA 09/2002 AT83C5134 8KB ROM 1024Bonly MLF package48MHz3V28, 32, 48, 64SOIC, QFN, MLF, VQFPSPI, TWI, USB 2.0B 03/2007 AT83C5135 16KB ROM 1024Bonly MLF package48MHz3V28, 32, 48, 64SOIC, QFN, MLF, VQFPSPI, TWI, USB 2.0B 03/2007 AT83C5136 32KB ROM 1024Bonly MLF package48MHz3V28, 32, 48, 64SOIC, QFN, MLF, VQFPSPI, TWI, USB 2.0B 03/2007 AT83EB5114 4KB ROM 256B256B24MHz3V20, 24SOICA 01/2005 AT89C1051 1KB 64B -none-24MHz3-5V20PDIP, SOICD 12/1997 AT89C2051 2KB 128B -none-24MHz3-5V20PDIP, SOICE 02/2000 AT89C4051 4KB 128B -none-24MHz3-5V20PDIP, SOICE 02/2000 AT89C51 4KB 128B -none-24MHz5V40, 44PDIP, TQFP, PLCCF 12/1997AT89C528KB256B -none-24MHz5V40, 44PDIP, TQFP, PLCCF 12/1997AT89C5520KB256B -none-33MHz5V40, 44PDIP, TQFP, PLCCD 12/1997AT89C55WD20KB256B -none-33MHz5V40, 44PDIP, TQFP, PLCCWatchDogB 09/2002 AT89C5115 16KB 256B/256B2KB40MHz3-5V24, 28, 32SOIC, PLCC, QFPF 05/2006 AT89C5130A-M 16KB 1024B4KB48MHz3-5V32, 52, 64QFN, PLCC, VQFPSPI, TWI, USB 2.0 - 03/2003 AT89C5131A-L 32KB 1024B4KB48MHz3V32, 52, 64QFN, PLCC, VQFPSPI, TWI, USB 2.0 - 03/2003 AT89C5131A-M 32KB 1024B4KB48MHz3-5V32, 52, 64QFN, PLCC, VQFPSPI, TWI, USB 2.0 - 03/2003 AT89C51AC2 32KB 1024B2KB40MHz3-5V44VQFP, PLCC - 04/2001 AT89C51AC3 64KB 2048B2KB60MHz3-5V44, 52, 64VQFP, PLCCA 10/2004 AT89C51ED2 64KB 256B/1792B2KB60MHz3-5V40, 44, 64, 68PDIP, PLCC, VQFP - 07/2003 E 04/2004 AT89C51IC2 32KB 256B/1KB -none-60MHz3V, 5V44PLC, VQFPTWIA 01/2004 AT89C51ID2 64KB 256B/1792B -none-60MHz3-5V44, 64, 68PLC, VQFPTWIA 09/2003 AT89C51RC 32KB 512B -none-33MHz5V40, 44PDIP, TQFP, PLCCB 11/2002 AT89C51RD2 64KB 256B/1792B -none-60MHz3-5V40, 44, 64, 68PDIP, PLCC, VQFP - 07/2003 E 04/2004 AT89EB5114 4KB 256B256B24MHz3V20, 24SOICInside AT24C02A 01/2005 AT89LP213 2KB 128B -none-20MHz2.4-5V14PDIP, TSSOPno UARTA 07/2006 AT89LP214 2KB 128B -none-20MHz2.4-5V14PDIP, TSSOPA 07/2006 AT89LP216 2KB 128B -none-20MHz2.4-5V16PDIP, SOIC, TSSOPA 06/2006 AT89LP2052 2KB 256B -none-20MHz2.4-5V20PDIP, SOIC, TSSOPA 03/2005 AT89LP3240 32KB 256B/4KB -none-20MHz2.4-3.6V40, 44PDIP, TQFP, PLCC, VQFN, MLFC 02/2011 AT89LP4052 4KB 256B -none-20MHz2.4-5V20PDIP, SOIC, TSSOPA 03/2005AT89LP4284KB256B/512B512B Flash20MHz2.4-5V28, 32PDIP, TQFP, PLCC, MLFA 08/2009AT89LP514KB256B256B Flash12MHz2.7V-5V40, 44PDIP, TQFP, PLCCB 12/2010AT89LP528KB256B256B Flash12MHz2.7V-5V40, 44PDIP, TQFP, PLCCB 12/2010 AT89LP6440 64KB 256B/4KB -none-20MHz2.4-3.6V40, 44PDIP, TQFP, PLCC, VQFN, MLFC 02/2011AT89LP8288KB256B/512B1KB Flash20MHz2.4-5V28, 32PDIP, TQFP, PLCC, MLFA 08/2009 AT89LS51 4KB 128B -none-16MHz3V40, 44PDIP, TQFP, PLCCISP, SPIA 05/2002 AT89LS52 8KB 256B -none-16MHz3V40, 44PDIP, TQFP, PLCCISP, SPIA 12/2001AT89LS5312KB256B -none-12MHz2.7V-5V40, 44PDIP, TQFP, PLCCISP, SPIC 03/2006AT89LS82528KB256B2KB12MHz3-5V40, 44PDIP, TQFP, PLCCISP, SPIC 03/2006AT89LV514KB128B -none-12MHz2.7V-5V40, 44PDIP, TQFP, PLCCISP, SPI? 12/1997AT89LV528KB256B -none-12MHz2.7V-5V40, 44PDIP, TQFP, PLCCISP, SPI? 12/1997AT89LV5520KB256B -none-12MHz2.7V-5V40, 44PDIP, TQFP, PLCCISP, SPI? 12/1997 AT89S2051 2KB 256B -none-24MHz3-5V20PDIP, SOICISP, SPIC 07/2005 AT89S4051 4KB 256B -none-24MHz3-5V20PDIP, SOICISP, SPIC 07/2005AT89S4D124KB256B128KB Flash12MHz3.3V28. 32SOIC, PLCCInside AT29LV010AA 12/1997 AT89S51 4KB 128B -none-33MHz5V40, 44PDIP, TQFP, PLCCISP, SPIA 10/2001AT89S528KB256B -none-33MHz5V40, 44PDIP, TQFP, PLCCISP, SPIA 07/2001 AT89S53 12KB 256B -none-24MHz5V40, 44PDIP, TQFP, PLCCISP, SPIE 03/2006 AT89S8252 8KB 256B2KB24MHz5V40, 44PDIP, TQFP, PLCCISP, SPIF 11/2003 AT89S8253 12KB 256B2KB24MHz3-5V40, 44PDIP, TQFP, PLCCISP, SPIH 09/2005

Port structures and operation

All four ports in the AT89C51 and AT89C52 are bidirectional. Each consists of a latch (Special Function Registers P0 through P3), an output driver, and an input buffer. The output drivers of Ports 0 and 2, and the input buffers of Port 0, are used in accesses to external memory. In this application, Port 0 outputs the low byte of the external memory address, time-multiplexed with the byte being written or read. Port 2 outputs the high byte of the external memory address when the address is 16 bits wide. Otherwise the Port 2 pins continue to emit the P2 SFR content. All the Port 3 pins, and two Port 1 pins (in the AT89C52)are multifunctional. The alternate functions can only be activated if the corresponding bit latch in the port SFR contains a 1. Otherwise the port pin is stuck at 0.

References

External links Atmel's 8051 family product page, updated link 09/23/2012