The AT89C1051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 1K bytes of Flash programmable and erasable Read-only memory (PEROM). The device is manufactured using Atmel's high-density non-volatile memory technology and is compatible with the industry standard MCS-51 instruction set.
Pin Configuration
The Atmel AT89C1051 is a powerful microcomputer that provides a highly flexible and cost effective solution for many embedded control applications by combining a versatile 8-bit CPU and Flash on a single chip. The AT89C1051 offers the following standard features :1K bytes of Flash, 64 bytes of RAM, 15 I/O lines, a 16-bit timer/counter, a three-vector two-stage interrupt architecture, a precision analog comparator, oscillator on chip, and clock circuits.
Block Diagram
In addition, the AT89C1051 is designed with static logic for operations as low as zero frequency and supports two software-optional power saving modes. Idle mode stops the CPU while allowing the RAM, timer/counter, serial port, and interrupt system to continue working. Power-off mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next hardware reset.
Special function register）
The following table shows the mapping of an on-chip memory region called a Special Function Register (SFR) space. Note that not all addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read access to these addresses usually returns random data, while write access has an uncertain effect. User software should not write a 1 to these unlisted locations, as they may be used in future products to invoke new functionality. In this case, the replacement or inactive value of the new bit will always be 0
Limitations of certain instructions）
The AT89C1051 is an affordable addition to Atmel's growing family of microcontrollers. It contains 1K bytes of flash program memory. It is fully compatible with the MCS-51 architecture and can be programmed using the MCS-51 instruction set. However, there are some considerations to keep in mind when programming the device with certain instructions. All instructions related to jumps or branches should be restricted so that the target address is within the physical program memory space of the device, which in the case of AT89C1051 is 1K. This should be the responsibility of the software programmer. For example, LJMP 3FEH would be a valid instruction for AT89C1051 (1K memory), while LJMP 410H would not be.
External Clock Drive Waveforms
