GSAS Peripheral IC Study Cards (8251/8253, 8255, 8259, 8279)

GSAS Peripheral IC Study Cards are a set of four plug-in interface cards designed for hands-on peripheral IC interfacing labs in microprocessor courses. Each card isolates a single peripheral IC on a dedicated PCB with all necessary support circuitry, I/O connectors, and clearly labelled test points, allowing students to focus on programming and interfacing one peripheral at a time without the complexity of a fully integrated system. The cards plug directly into the expansion bus connector on GSAS 8085 and 8086 Trainer Kits.

The four-card set covers the core peripheral ICs specified in Indian university microprocessor syllabi: the 8251 USART and 8253 Timer (combined on one card for serial communication and timing experiments), the 8255 Programmable Peripheral Interface for parallel I/O modes, the 8259 Programmable Interrupt Controller for interrupt handling, and the 8279 Keyboard/Display Controller for multiplexed keyboard scanning and display driving. Together, these cards provide complete coverage of the peripheral interfacing portion of standard microprocessor lab courses.

Each study card includes clearly documented I/O connections, on-board LEDs and switches for immediate visual feedback, and compatibility with the structured lab manual provided by GSAS. The modular approach means colleges can purchase cards individually or as a complete set, and replace individual cards if needed without affecting the rest of the lab setup.

Study Card Comparison

Card	IC(s)	Function	Key Experiments
8251/8253 Card	Intel 8251A USART + 8253 PIT	Serial communication + timer/counter	Baud rate generation, serial data TX/RX, square wave generation, event counting
8255 Card	Intel 8255A PPI	Programmable parallel I/O	Mode 0 simple I/O, Mode 1 strobed I/O, Mode 2 bidirectional, BSR mode
8259 Card	Intel 8259A PIC	Programmable interrupt control	Single PIC setup, interrupt priority modes, ISR programming, EOI handling
8279 Card	Intel 8279	Keyboard/display controller	Scanned keyboard mode, display scan, FIFO read, encoded/decoded modes

Peripheral IC Details

Peripheral IC	Type	Key Capability
8251A	Universal Synchronous/Asynchronous Receiver-Transmitter	Synchronous and asynchronous serial data communication
8253	Programmable Interval Timer	Three independent 16-bit counters with 6 operating modes
8255A	Programmable Peripheral Interface	Three 8-bit I/O ports with three operating modes
8259A	Programmable Interrupt Controller	Eight interrupt levels with priority resolution and masking
8279	Keyboard/Display Controller	Scanned keyboard input and multiplexed display output

Compatibility

All four study cards are designed to plug into the standard GSAS trainer expansion bus and are compatible with:

• GSAS 8085 Trainer Kit
• GSAS 8086/8088 Trainer Kit
• GSAS 8051 Trainer Kit

No additional wiring, adapters, or power supplies are required, the cards draw power and bus signals directly from the trainer through the expansion connector.

Why GSAS

GSAS manufactures these study cards in-house in Bangalore, ensuring consistent quality and immediate availability. The modular study card approach has been proven across hundreds of Indian engineering college labs, providing a structured progression from basic microprocessor programming to peripheral interfacing. Colleges deploying new labs can order complete sets (trainer plus all four study cards) at volume pricing, while existing labs can order individual replacement cards as needed.

Products are available for immediate purchase through the GSAS online store (“Buy on Store”) or through direct engagement for institutional and volume orders (“Request Volume Pricing”).