Atmel AT89 series explained

The Atmel AT89 series is an Intel 8051-compatible family of 8 bit microcontrollers (μCs) manufactured by the Atmel Corporation.

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 memory size	Data memory size
AT80C51RD2^[1]	64KB Flash^[2]	1024 bytes RAM
AT83C5134^[3]	-none-	1024 bytes RAM
AT83C5135^[4]	-none-	1024 bytes RAM
AT83C5136^[5]	-none-	1024 bytes RAM
AT83EB5114^[6]	-none-^[7]	256 bytes RAM
AT89C1051	1KB Flash	64 bytes RAM
AT89C2051^[8]	2KB Flash	128 bytes RAM^[9]
AT89C4051^[10]	4KB Flash	128 bytes RAM^[11]
AT89C51/S51	4KB Flash	128 bytes RAM
AT89C5115^[12]	16KB Flash	256 bytes RAM^[13]
AT89C5130A-M^[14]	16KB Flash	1024 bytes RAM
AT89C5131A-L^[15]	32KB Flash	1024 bytes RAM
AT89C5131A-M^[16]	32KB Flash	1024 bytes RAM
AT89C51AC2^[17]	32KB Flash	1024 bytes RAM
AT89C51AC3^[18]	64KB Flash	2048 bytes RAM
AT89C51ED2^[19]	64KB Flash	1792 bytes RAM
AT89C51IC2^[20]	32KB Flash	256 bytes RAM
AT89C51ID2^[21]	64KB Flash	1792 bytes RAM
AT89C51RC^[22]	32KB Flash	512 bytes RAM
AT89C51RD2^[23]	64KB Flash	1792 bytes RAM
AT89C52/S52^[24]	8KB Flash	256 bytes RAM^[25]
AT89C55/55WD^[26]	20KB Flash	256 bytes RAM
AT89EB5114^[27]	4KB Flash	256 bytes RAM
AT89LP213^[28]	2KB Flash	128 bytes RAM^[29]
AT89LP214^[30]	2KB Flash	128 bytes RAM
AT89LP216^[31]	2KB Flash	128 bytes RAM^[32]
AT89LP2052^[33]	2KB Flash	256 bytes RAM^[34]
AT89LP3240^[35]	64KB Flash	4352 bytes RAM
AT89LP4052^[36]	4KB Flash	256 bytes RAM
AT89LP6440^[37]	64KB Flash	4352 bytes RAM
AT89LS51^[38]	4KB Flash	128 bytes RAM^[39]
AT89LS52^[40]	8KB Flash	256 bytes RAM^[41]
AT89S2051^[42]	2KB Flash	256 bytes RAM^[43]
AT89S4051^[44]	4KB Flash	256 bytes RAM
AT89S51^[45]	4KB Flash	128 bytes RAM^[46]
AT89S53	12KB Flash	256 bytes RAM
AT89S8252^[47]	8KB Flash	256 bytes RAM
AT89S8253^[48]	8KB Flash	256 bytes RAM

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.

External links

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

Notes and References

1. Web site: AT80C51RD2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
2. Web site: Ferret . www.microchip.com . 13 September 2020.
3. Web site: AT83C5134 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
4. Web site: AT83C5135 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
5. Web site: AT83C5136 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
6. Web site: AT83EB5114 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
7. Web site: AT83EB5114 AT89EB5114 . www.microchip.com . 13 September 2020.
8. Web site: AT89C2051 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
9. Web site: AT89C2051 . microchip.com . 13 September 2020.
10. Web site: AT89C4051 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
11. Web site: AT89C4051 . microchip.com . 13 September 2020 . 5 August 2012.
12. Web site: AT89C5115 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
13. Web site: Low Pin Count 8-bit MCU with A/D converter and 16 KB Flash Memory . www.microchip.com . 13 September 2020.
14. Web site: AT89C5130A-M - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
15. Web site: AT89C5131A-L - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
16. Web site: AT89C5131A-M - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
17. Web site: AT89C51AC2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
18. Web site: AT89C51AC3 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
19. Web site: AT89C51ED2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
20. Web site: AT89C51IC2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
21. Web site: AT89C51ID2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
22. Web site: AT89C51RC - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
23. Web site: AT89C51RD2 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
24. Web site: AT89S52 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
25. Web site: AT89S52 . www.microchip.com . 13 September 2020.
26. Web site: AT89C55/55WD - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
27. Web site: AT89EB5114 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
28. Web site: AT89LP213 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
29. Web site: 3538E.book . microchip.com . 13 September 2020.
30. Web site: AT89LP214 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
31. Web site: AT89LP216 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
32. Web site: 3621E.book . microchip.com . 13 September 2020.
33. Web site: AT89LP2052 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
34. Web site: 3547J.book . microchip.com . 13 September 2020.
35. Web site: AT89LP3240 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
36. Web site: AT89LP4052 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
37. Web site: AT89LP6440 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
38. Web site: AT89LS51 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
39. Web site: AT89LS51 . www.microchip.com . 13 September 2020.
40. Web site: AT89LS52 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
41. Web site: AT89LS52 . www.microchip.com . 13 September 2020.
42. Web site: AT89S2051 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
43. Web site: AT89S2051/S4051 Preliminary Datasheet . microchip.com . 13 September 2020.
44. Web site: AT89S4051 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
45. Web site: AT89S51 - Microcontrollers and Processors . www.microchip.com . 13 September 2020.
46. Web site: AT89S51 . www.microchip.com . 13 September 2020.
47. Web site: AT89S8252 . microchip.com . 13 September 2020.
48. Web site: AT89S8253 - Microcontrollers and Processors . microchip.com . 13 September 2020.