This is the Revision D verion of the Digital8 module. The status of this project is finished.

Digital8 Module (Revision D)

Table of Contents

This document is also available in PDF format.

• 1. Introduction
• 2. Programming
• 3. Hardware
  • 3.1 Circuit Schematic
  • 3.2 Printed Circuit Board
• 4. Software
• 5. Issues

1. Introduction

The Digital8 module provides the ability to input and output 8 bits of digital data. The direction of each bit can be changed under program control.

2. Programming

The programmer can download a complement mask to cause any of the bits to be complemented prior to reading.

The Digital8 module supports the Interrupt Protocol. The interrupt pending bit is set whenever the the formula:

L&(~I) | H&I | R&(~P)&I | F&P&(~I)]

• I is the current input bits XOR'ed with the complement mask (C)
• P is the previous value of I
• L is the low mask
• H is the high mask
• R is the raising mask
• F is the falling mask

• ~ is bit-wise complement
• | is bit-wise OR
• & is bit-wise AND

The Digital8 module supports both the standard shared commands and the shared interrupt commands in addition to the following commands:

Command	Send/ Receive	Byte Value								Discussion
		7	6	5	4	3	2	1	0
Read Inputs	Send	0	0	0	0	0	0	0	0	Return 8-bits of input iiii iiii (after XOR'ing with complement mask)
	Receive	i	i	i	i	i	i	i	i
Read Outputs	Send	0	0	0	0	0	0	0	1	Return 8-bits of the outputs oooo oooo (after XOR'ing with complement mask.)
	Receive	o	o	o	o	o	o	o	o
Read Complement Mask	Send	0	0	0	0	0	0	1	0	Return 8-bits of complement mask cccc cccc
	Receive	c	c	c	c	c	c	c	c
Read Direction Mask	Send	0	0	0	0	0	0	1	1	Return 8-bits of direction mask dddd dddd
	Receive	d	d	d	d	d	d	d	d
Read Low Mask	Send	0	0	0	0	0	1	0	0	Return 8-bits of low mask llll llll
	Receive	l	l	l	l	l	l	l	l
Read High Mask	Send	0	0	0	0	0	1	0	1	Return 8-bits of the high mask hhhh hhhh
	Receive	h	h	h	h	h	h	h	h
Read Rising Mask	Send	0	0	0	0	0	1	1	0	Return 8-bits of the rising mask rrrr rrrr
	Receive	r	r	r	r	r	r	r	r
Read Falling Mask	Send	0	0	0	0	0	1	1	1	Return 8-bits of the falling mask ffff ffff
	Receive	f	f	f	f	f	f	f	f
Read Inputs Raw	Send	0	0	0	0	1	0	0	0	Return raw inputs rrrr rrrr/Em> (no XOR with complement mask)
	Receive	r	r	r	r	r	r	r	r
Read Analog Mask	Send	0	0	0	0	1	0	0	1	Return 8 bit analog mask aaaa aaaa
	Receive	a	a	a	a	a	a	a	a
Read Outputs Raw	Send	0	0	0	0	1	0	1	0	Return raw outputs rrrr rrrr (no XOR with complement mask)
	Receive	r	r	r	r	r	r	r	r
Read Analog Vref	Send	0	0	0	0	1	0	1	1	Return analog Vref v
	Receive	0	0	0	0	0	0	0	v
Reset Outputs	Send	0	0	0	1	0	0	0	0	Set all 8 bits of outputs to 0 (then XOR with complement mask).
Set Outputs	Send	0	0	0	1	0	0	0	1	Set output bits to oooo oooo.
	Send	o	o	o	o	o	o	o	o
Set Complement Mask	Send	0	0	0	1	0	0	1	0	Set 8-bits of complement mask to cccc cccc
	Send	c	c	c	c	c	c	c	c
Set Direction Mask	Send	0	0	0	1	0	0	1	1	Set 8-bits of direction mask to dddd dddd 1=input; 0=output
	Send	d	d	d	d	d	d	d	d
Set Low Mask	Send	0	0	0	1	0	1	0	0	Set 8-bits of low mask to llll llll
	Send	l	l	l	l	l	l	l	l
Set High Mask	Send	0	0	0	1	0	1	0	1	Set 8-bits of the high mask to hhhh hhhh
	Send	h	h	h	h	h	h	h	h
Set Rising Mask	Send	0	0	0	1	0	1	1	0	Set 8-bits of the rising mask to rrrr rrrr
	Send	r	r	r	r	r	r	r	r
Set Falling Mask	Send	0	0	0	1	0	1	1	1	Set 8-bits of the falling mask to ffff ffff
	Send	f	f	f	f	f	f	f	f
Set Outputs Raw	Send	0	0	0	1	1	0	0	0	Set 8-bits to oooo oooo with no complement mask.
	Send	o	o	o	o	o	o	o	o
Set Analog Mask	Send	0	0	0	1	1	0	0	1	Set analog mask to mmmm mmmm.
	Receive	a	a	a	a	a	a	a	a
Set Vref Mode	Send	0	0	0	1	1	0	1	v	Set Vref mode to v.
Reset Everything	Send	0	0	0	1	1	1	1	1	Reset all registers to 0 and set direction bits to 1 (input)
Set Output Bit	Send	0	0	1	0	v	b	b	b	Set output bit bbbb to v
Set Outputs Low	Send	0	1	0	0	l	l	l	l	Set low order 4-bits of Outputs to llll and then XOR complement mask
Set Outputs High	Send	0	1	0	1	h	h	h	h	Set high order 4-bits of Outputs to hhhh and and then XOR complement mask
Set Direction Low	Send	0	1	1	0	l	l	l	l	Set low order 4-bits of direction to llll.
Set Direction High	Send	0	1	1	1	h	h	h	h	Set high order 4-bits of direction to hhhh.
Read Analog 8-bits	Send	1	0	0	0	0	b	b	b	Read 8-bits of analog data aaaa aaaa from port bbb.
	Receive	a	a	a	a	a	a	a	a
Read Analog 10-bits	Send	1	0	0	0	1	b	b	b	Read 10-bits of analog data aaaa aaaa ll00 000 from port bbb.
	Receive	a	a	a	a	a	a	a	a
	Receive	l	l	0	0	0	0	0	0
Set Interrupt Commands	Send	1	1	1	1	0	c	c	c	Set Interrupt Command ccc.
Shared Commands	Send	1	1	1	1	1	c	c	c	Execute Shared Command ccc

3. Hardware

The hardware consists of a circuit schematic and a printed circuit board.

3.1 Circuit Schematic

The schematic for the Digital8 module is shown below:

The parts list kept in a separate file -- digital8.ptl.

3.2 Printed Circuit Board

The printed circuit files are listed below:

digital8_back.png

The solder side layer.

digital8_front.png

The component side layer.

digital8_artwork.png

The artwork layer.

digital8.gbl

The RS-274X "Gerber" back (solder side) layer.

digital8.gtl

The RS-274X "Gerber" top (component side) layer.

digital8.gal

The RS-274X "Gerber" artwork layer.

digital8.drl

The "Excellon" NC drill file.

digital8.tol

The "Excellon" tool rack file.

3.3 Construction Instructions

The construction Instructions are located in a separate file to be a little more printer friendly.

4. Software

The Digital8 software is available as one of:

digital8.ucl

The µCL source file.

digital8.asm

The resulting human readable PIC assembly file.

digital8.lst

The resulting human readable PIC listing file.

digital8.hex

The resulting Intel^® Hex file.

5. Issues

Any fabrication issues will be listed here.