
S Y S T E M C O N T R O L M O D U L E
How the quadrature decoder/counter works
146
Hardware Reference NS9215
A quadrature decoder/counter module performs these tasks at real time speed and
interrupts the CPU at the predetermined conditions.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
H o w t h e q u a d r a t u r e d e c o d e r / c o u n t e r w o r k s
Provides input
signals
A quadrature encoder provides a pair of signals (in-phase and quad-phase) with
opposite polarities and a 90-degree phase shift. Decode these signals to create an
algorithm to determine the direction, speed, and position of a motion wheel.
Input signals
Quadrature
encoding truth
table
Legend:
NC — No change
CW — Clockwise
CCW — Counter clockwise
Err — Error
00
01
10
11
00
01
10
11
00
00
10
01
01
00
11
Clockwise
Counter
Clockwise
I:Q
00
01
10
11
00
NC
CW
CCW
Err
01
CCW
NC
Err
CW
10
CW
Err
NC
CCW
11
Err
CCW
CW
NC
Summary of Contents for NS9215
Page 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Page 3: ......
Page 4: ......
Page 26: ...26 Hardware Reference NS9215...
Page 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Page 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Page 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Page 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Page 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Page 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Page 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Page 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Page 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Page 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...