Introduction

The VipStick is an extension to the SimmStick specification for multiplexing peripherals on a shared bus. It allows one master processor to communicate with up to 8 slave peripherals using a shared 8 bit bus.

The purpose of this specification is to promote a component based toolbox of peripherals for SimmStick development projects. Instead of trying to fit as much functionality as possible onto a single board,

The specification uses the SCL line on the SimmStick bus as well as the 8 bits of port B of the PIC (SimmStick lines D0 - D7) to the multiplexed communications. However, when not addressing a VipStick slave device, 6 of these bits may be used by other devices on the bus. This would allow several VipStick peripherals to share the same bus as a 6 pin LCD interface as specified in PicBasicPro or another device.

This is essentially a design for putting SPI type peripherals on the SimmStick bus. The SCL, MISO, and MOSI signal names come from SPI nomenclature. Other serial protocols (I2C, Microwire, Dallas 1-Wire, etc.) can easily be implemented as well. No communications protocol is specified - only the address match and signal connection functionality.

VipStick slave peripherals are intended to be primarily synchronous serial IO devices.

This specification defines the VipStick bus pin assignments, usage, and slave requirements as well as the requirements placed on non-VipStick devices which will share the bus. Specifically, the specification covers:

	Pin Assignments
	Addressing Capabilities
	Shared Signal Connect/Disconnect
	Address and IO Functionality
	Slave Interrupt Requests of the Master
	Software/Hardware Flow of Control
	Example Hardware Implementation of the Slave Peripheral

In addition, examples of VipStick peripherals and system designs are given.

For questions or comments, email vipstick@vipstick.com

The specific benefits of this system include the ability to build up a project from a set of "plug and play" components. This avoids any need to design each SimmStick peripheral for an individual SimmStick processor. Using a motherboard (DT001, DT003, DT004 or even a DT204), an unmodified processor board (e.g., DT101, etc.), and a selection of peripherals using the VipStick extensions, a project can be built very quickly. The software required to communicate with each VipStick may be a bit different, but the hardware will be standard. Many of the peripherals will use a synchronous serial communications protocol.

A few of the VipSticks possible include:

	4 to 8 digit seven segment LED display
	16 input, 16 output I/O board
	Relay or high current transistor controller card
	X10 Automation interface board
	Keypad interface board
	LCD display board
	iButton Microlan interface board
	Serial Weather Station interface board
	Sound card (Frequency, DTMF, Holtek chips) with on board speaker
	Ultrasonic ranging card
	I/R ranger or obstacle avoidance board
	High capacity serial EEPROM board
	Basic Stamp II carrier board

And, a few examples:

	An intelligent sprinkler controller - DT003 motherboard with RS-232 interface for connection to host pc for programming, a DT101 with real-time clock and serial eeprom for the processor and and memory, an LCD board for local display, an X10 board for home automation integration.
	A modular burglar alarm - Motherboard, processor and clock, a 16 bit I/O card for each monitored zone, X10 interface, keypad interface, LCD interface.
	A Mobile Robot - Motherboard, processor,16 bit I/O, I/R object detection and ranging, sound card with speaker.
	Digital Optical Tachometer - Motherboard, processor, I/R object detection, 4 digit LED display.

All of these examples can be prototyped very quickly when the designer has these boards in the toolbox. This is how the SimmStick is meant to be used.

Continue to the VipStick Specification.