Z8S18020VEG

Overview

The Z8S18020VEG is a static microprocessor based on the Z180 core, operating at a maximum clock frequency of 20 MHz. It features an 8-bit data bus and supports up to 1 MB of addressable memory via its Memory Management Unit. The device integrates two DMA channels, two enhanced UARTs, two 16-bit timers, and a Clocked Serial I/O port. It operates on a single 5V supply with an industrial temperature range of -40°C to +85°C and is housed in a 68-pin PLCC package.

Feature Summary

• Code-compatible with ZiLOG Z80 CPU while offering extended instructions and faster execution speeds.
• Integrates two chain-linked DMA channels for high-speed memory-to-memory or I/O transfers.
• Includes two enhanced UARTs with programmable baud rate generators supporting asynchronous data rates up to 512 Kbps.
• Provides multiple low-power-down modes including Stop, Sleep, and Power-Down to reduce system energy consumption.

Applications

• Industrial control systems requiring robust interrupt handling and serial communication.
• Embedded applications needing direct memory access capabilities for peripheral interfacing.
• Battery-powered devices utilizing low-power stop and sleep modes for extended operation.
• Legacy system upgrades replacing standard Z80 processors with enhanced functionality.

Procurement Notes

Verify component authenticity through authorized distributors as this part may be subject to obsolescence notices. Confirm that the specific ordering suffix corresponds to the required voltage and temperature grade. Ensure design-in compatibility with existing PCB footprints for the 68-pin PLCC package. Review official discontinuation notifications for lifecycle status before finalizing procurement plans.

Selection Notes

Select this model when backward compatibility with Z80 software is mandatory alongside enhanced I/O resources. Consider the 20 MHz speed rating against system timing requirements and external memory access constraints. Evaluate the need for dual UARTs and DMA channels versus simpler variants like the Z8L180 if power consumption is less critical than feature density.

Part Context

This component belongs to the Z8S180 family, which enhances the original Z80180 architecture by adding static operation and improved power management. It serves as a bridge between legacy Z80 ecosystems and modern embedded requirements, offering expanded addressing and integrated peripherals without requiring complete architectural redesigns.

Replacement Considerations

Public confirmed substitute part numbers: Z8S18020FSG, Z8S18020FEG, Z8S18010FSG, Z8S18010VEG, Z8S18010FEG.

FAQ

Does the Z8S18020VEG support dynamic RAM refresh?

Yes, the processor includes a dedicated DRAM refresh output signal (REF) that works in conjunction with the memory request signal to manage dynamic memory maintenance cycles.

What is the function of the MMU in this microprocessor?

The Memory Management Unit allows the user to map the logically limited 64KB memory space into the full 1MB addressing range supported by the Z8S180/Z8L180 architecture using a common-area/banked-area scheme.

How does the CSI/O channel operate regarding duplexing?

The Clocked Serial I/O channel provides half-duplex transmission and reception. Transmit and receive operations cannot occur simultaneously, and the system design must ensure constraints are met to prevent data corruption.