The 8155 Datasheet is more than just a document; it’s a comprehensive guide to understanding and utilizing the Intel 8155/8156, a versatile static RAM with I/O ports and a timer. This article breaks down the key elements of the 8155 Datasheet, making it accessible to anyone interested in embedded systems and microcontroller programming.
Understanding the 8155 Datasheet A Comprehensive Guide
The 8155 Datasheet serves as the primary reference for anyone working with the Intel 8155/8156 chip. It contains detailed information about the chip’s architecture, pin configuration, electrical characteristics, and timing diagrams. Without the 8155 Datasheet, effective implementation and troubleshooting are virtually impossible. It is your indispensable roadmap for successful hardware and software integration. In essence, the datasheet provides the necessary details to interface the 8155/8156 with a microprocessor, control its I/O ports, and leverage its built-in timer for various applications.
The 8155 and 8156 are essentially the same device except for the Chip Enable pin. The 8155 has one active-low Chip Enable pin, whereas the 8156 has two chip enable pins, one active-high, and one active-low, which offers some added flexibility in address decoding. The 8155 Datasheet reveals specifications such as:
- RAM size (typically 256 bytes)
- Number of I/O ports (usually 3, with varying configurations)
- Timer frequency and modes of operation
The datasheet includes a description of all the control registers used to configure all the functions. Understanding the datasheet is crucial for choosing the right address mapping and configuring the I/O ports for input or output, as well as setting up the timer for specific interrupt intervals or pulse generation.
Consider a simple example: you want to use the 8155 to control an LED connected to one of its I/O pins. The 8155 Datasheet guides you through the process of configuring that specific pin as an output and then writing the appropriate data (HIGH or LOW) to turn the LED on or off. Furthermore, if you need to generate a periodic signal to blink the LED, the datasheet provides the necessary information to program the timer and set up an interrupt routine. The 8155 Datasheet is also vital for understanding timing constraints, ensuring that your microprocessor interacts with the 8155 within the allowed timing windows to prevent data corruption or unpredictable behavior. A quick summary of its features are listed as:
- 256 x 8 static RAM
- Two 8-bit parallel I/O ports
- One 6-bit parallel I/O port
- 14-bit timer/counter
Below is a table summarizing the important function of each pin
| Pin Name | Function |
|---|---|
| AD0-AD7 | Address/Data Bus |
| CE | Chip Enable |
| IO/M | I/O or Memory Select |
Ready to delve deeper into the specifics? You can review the entire 8155 Datasheet available in PDF format. It is the best place to find detailed information about the chip’s characteristics and functionalities.