DM164120-1 Microchip Technology, DM164120-1 Datasheet - Page 38

• Manufacturer Part Number: DM164120-1
• Description: BOARD DEMO PICKIT 2 LP COUNT
• Manufacturer: Microchip Technology
• Type: MCUr

Specifications of DM164120-1

• Contents: 3 Boards (1 Populated, 2 Bare)
• Processor To Be Evaluated: PIC16F690
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC16
• Silicon Core Number: PIC16F
• Silicon Family Name: PIC16F6xxx
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: 28-pin PIC16C, 16F, 18C, 18F
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Low Pin Count Demo Board User’s Guide
DS51556A-page 34
This lesson uses the Look-up Table to implement a binary to Gray code converter. Gray
code is a binary code in which only a single bit changes from one sequence to the next.
They are frequently used in encoder applications to avoid wild jumps between states.
Binary encoders are typically implemented an opaque disk sensed by light sensors.
Due to different threshold levels on different bits, bits may change at slightly differently
times yielding momentary invalid results. Gray code prevents this because only one bit
changes from one sequence to the next. The current code is correct until it transitions
to the next.
The algorithm to convert between binary and Gray code is fairly complex. For a small
number of bits, the table look-up is smaller and faster.
This lesson also takes the Analog-to-Digital value and converts it to Gray code
displayed on the LEDs. The code changes one bit at a time as the potentiometer
rotates across its range (see Example 3-12).
Gray Code Converter
Decimal
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Binary
0000
0001
0011
0010
0110
0111
0101
0100
1100
1101
1111
1110
1010
1011
1001
1000
© 2005 Microchip Technology Inc.