MCP355XDV-MS1 Microchip Technology, MCP355XDV-MS1 Datasheet - Page 17

• Manufacturer Part Number: MCP355XDV-MS1
• Description: BOARD DEV SENSOR APP MCP355X
• Manufacturer: Microchip Technology

Specifications of MCP355XDV-MS1

• Number Of Adc's: 1
• Number Of Bits: 22
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: ±0.3 V
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: MCP355x
• Processor To Be Evaluated: MCP355x
• Interface Type: RS-232, USB
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Not applicable / Not applicable

3.1
3.2
© 2006 Microchip Technology Inc.
FIRMWARE OVERVIEW
PIC16F877
The MCP355X Sensor Application Developer’s Board contains two PICmicro MCUs,
the PIC18F4550, which is solely used to send ADC data to DataView on the PC and
the PIC16F877 which interfaces to the LCD display. Both controllers come pro-
grammed with dedicated firmware that is described in this chapter.
This device comes programmed with LCD firmware to ease weigh scale or other
system design. The three push buttons F1, F2, and F3 control both the MCP3551
sampling and LCD output through the PIC16F877.
3.2.1
This display will change depending on the units selected and the values that are loaded
into the zero calibrate, full-scale calibrate, and full-scale value registers. To show raw
ADC output, the unit menu is used to select A/D units. When grams (g), or kilograms
(kg) is selected, Equation 3-1 represents the algorithm and formula applied to yield an
output on the LCD display.
EQUATION 3-1:
Where:
Chapter 3. Firmware Description
DISPLAY_FS_VAL
Note:
DEVELOPER’S BOARD USER’S GUIDE
LCD Numerical Output Display
Output
ZERO
The ZERO
disabled. See Section 3.2.2.1 “Zero calibrate” for complete
description
ADC
FS
CAL
CAL
VAL
MCP355X SENSOR APPLICATION
=
=
=
=
=
CAL
⎛
⎝
ADC
--------------------------------------------------- -
The most recent value from the ADC after averaging.
The most recent ADC
is pressed.
The most recent (ADC
calibrate full-scale switch is pressed.
1, 2, 5, 10, 20, 50, 100, 200, or 500 (value selected
using push button switches.)
See Section 3.2.2.5 “Full-Scale Value Selection”
subtraction to remove zero offset can be enabled or
VAL
FS
–
CAL
ZERO
CAL
VAL
⎞
⎠
VAL
×
when the calibrate zero switch
DISPLAY_FS_VAL
- ZERO
CAL
) when the
DS51609A-page 13