This is revision A of the Bumper14 module.

Bumper14 Module (Revision A)

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

1. Introduction

The Bumper14 module provides 14 inputs for simple electrical switch closures.

2. Programming

Command
Name Action Bit Description
8 7 6 5 4 3 2 1 0

Common
Commands Send 0 1 1 1 1 1 x x x Standard common command. See specifications for details.
Receive 0 a a a a a a a a

Select Send 1 a a a a a a a a Select the module with an address of aaaa aaaa. A time-out indicates that the module is not selected; otherwise 1010 0101 (0xa5) is returned to indicate a successful selection.
Receive 0 1 0 1 0 0 1 0 1

Command Name	Action	Bit	Description
8	7	6	5	4	3	2	1	0
Common Commands	Send	0	1	1	1	1	1	x	x	x	Standard common command. See specifications for details.
Receive	0	a	a	a	a	a	a	a	a
Select	Send	1	a	a	a	a	a	a	a	a	Select the module with an address of aaaa aaaa. A time-out indicates that the module is not selected; otherwise 1010 0101 (0xa5) is returned to indicate a successful selection.
Receive	0	1	0	1	0	0	1	0	1

3. Hardware

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

The parts list kept in a separate file -- bumper14.ptl.

3.1 Circuit Schematic

The schematic for the Bumper14 module is shown below:

The bus is connected to the 2×5 shrouded conenctor N9. The two CAN bus signals are fed into the PCP2551 CAN bus transceiver U2. The output of U2 is fed to the UART transmit and receive signals on the PIC16F688 microcontroller U1. 8-pins of the U1 are connected to 1×3; polarized .1" male headers. Each pin is connected to one of the anlog inputs on U1. A half size crystal oscillator (X1) is used to provide the reference 20MHz signal. A resonator could not be used since it requires pins 2 and 3 of U1, and pin 3 is needed for a analog input (AN3).

3.2 Printed Circuit Board

The printed circuit board files are listed below:

bumper14_back.png: The solder side layer.
bumper14_front.png: The component side layer.
bumper14_artwork.png: The artwork layer.
bumper14.gbl: The RS-274X "Gerber" back (solder side) layer.
bumper14.gtl: The RS-274X "Gerber" top (component side) layer.
bumper14.gal: The RS-274X "Gerber" artwork layer.
bumper14.gml: The RS-274X "Gerber" mask layer.
bumper14.drl: The "Excellon" NC drill file.
bumper14.tol: The "Excellon" tool rack file.

4. Software

The following files are available:

bumper14.ucl: The µCL source code for the Bumper14 module.
bumper14.asm: The Bumper14 module assembly code file.
bumper14.lst: The Bumper14 module listing file.
bumper14.hex: The µCL Bumper14 Intel^® Hex file.

5. Issues

Any fabrication issues will be listed here.