 2004 Microchip Technology Inc.

DS00897B-page 13

AN897

A.2.6

FIRMWARE FOR THE SIGNAL

ANALYSIS PICtail DAUGHTER

BOARD

PICA2Dlab.hex

is the standard file that supports the

PICkit™ 1 Signal Analysis PC Program. The PGA and

10-bit ADC configuration are selected in the Signal

Analysis PC Program and written to the PIC16F684.

The PIC16F684 then sends the command(s) over the

SPI bus to the PGA.

Therm_PGA1.hex

implements the first design. It

supports the PICkit 1 Signal Analysis PC Program, but

with reduced functionality; its output can be viewed on

the strip chart only. The results need to be manually

converted to temperatures (codes 0 to 1023 convert to

0.0°C to 102.3°C).

Therm_PGA2.hex

implements the second design. It

supports the PICkit 1 Signal Analysis PC Program, but

with reduced functionality; its output can be viewed on

the strip chart only. The results need to be manually

converted to temperatures (codes 0 to 1023 convert to

0.0°C to 102.3°C).

A.2.7

INTERFACE DETAILS

A more detailed look at how the Thermistor PGA PICtail

Daughter Board interfaces with the other boards is

shown in Figure A-4.

FIGURE A-4:

Detailed Interface Diagram.

Thermistor

Voltage

Divider

PGA

MCP6S22

Thermistor PGA

PICtail™ Daughter Board

SPI Bus

4

Serial

EEPROM

PIC16F684

ADC

Signal Analysis

PICtail™ Daughter Board

GND

+5V

GND

+5V

PICkit™ 1

Flash Starter Kit

4

SPI™ Bus

CH1 Input

CH0 Input

+5V

GND

Test Point

Test Point

Test Point

Test Point

2

PIC16F745

USB

to PC

Temperature