R6532 RAM-I/O-Timer (RIOT) Integrated Circuit (DIP-40)

The R6532, commonly known as the RIOT (RAM, I/O, Timer) chip, is a highly integrated multifunction peripheral designed to support the 6500 series microprocessor family. It combines three essential system functions into a single 40-pin package: 128 bytes of static RAM, two 8-bit software-programmable bidirectional I/O ports, and a versatile interval timer. The I/O ports allow each pin to be individually configured as an input or output, providing significant flexibility for controlling LEDs, reading switches, or communicating with other digital logic. The internal timer can be programmed to count in increments of 1, 8, 64, or 1024 clock cycles, making it ideal for managing precise delays or generating periodic interrupts. Because of its high level of integration, the R6532 was famously used in early home video game consoles like the Atari 2600 to minimize chip count and system cost while providing necessary memory and control interfaces.

Key Features:

Two 8-bit bidirectional peripheral I/O ports for flexible device interfacing.

Programmable interval timer with interrupt capability and selectable prescalers.

Directly compatible with the 6502 family of microprocessors and buses.

Features programmable edge-active interrupt inputs for real-time sensing.

Single 5V power supply operation with low power consumption characteristics.