参数资料
型号: HCTL-2032
元件分类: 通用总线功能
英文描述: Quadrature Decoder/Counter Interface ICs
中文描述: 正交解码器/计数器接口芯片
文件页数: 14/20页
文件大小: 302K
代理商: HCTL-2032
14
Design Considerations
The designer should be aware
that the operation of the digital
filter places a timing constraint
on the relationship between
incoming quadrature signals and
the external clock. Figure 12
shows the timing waveform with
an incremental encoder input.
Since an input has to be stable
for three rising clock edges, the
encoder pulse width (t
E
- low
or high) has to be greater than
three clock periods (3t
CLK
). This
guarantees that the
asynchronous input will be
stable during three consecutive
rising clock edges. A realistic
design also has to take into
account finite rise time of the
waveforms, asymmetry of the
waveforms, and noise. In the
presence of large amounts of
noise, t
E
should be much
greater than 3t
CLK
to allow for
the interruption of the
consecutive level sampling by
the three-bit delay filter. It
should be noted that a change
on the inputs that is qualified
by the filter will internally
propagate in a maximum of
seven clock periods.
The quadrature decoder
circuitry imposes a second
timing constraint between the
external clock and the input
signals. There must be at least
one clock period between
consecutive quadrature states.
As shown in Figure 13, a
quadrature state is defined by
consecutive edges on both
channels. Therefore, t
ES
(encoder state period) > t
CLK
.
The designer must account for
deviations from the nominal 90
degree phasing of input signals
to guarantee that t
ES
> t
CLK
.
Position Counter
This section consists of a 32-bit
(HCTL-20XX-XX) binary up/
down counter which counts on
rising clock edges as explained
in the Quadrature Decoder
Section. All 32 bits of data are
passed to the position data
latch. The system can use this
count data in several ways:
A. System total range is 32 bits,
so the count represents
"absolute" position.
B. The system is cyclic with 32
bits of count per cycle. RST/ is
used to reset the counter every
cycle and the system uses the
data to interpolate within the
cycle.
C. System count is >8, 16, 24, or
32 bits, so the count data is
used as a relative or
incremental position input for a
system software computation of
absolute position. In this case
counter rollover occurs. In order
to prevent loss of position
information, the processor must
read the outputs of the IC
before the count increments
one-half of the maximum count
capability. Two's-complement
arithmetic is normally used to
compute position from these
periodic position updates.
D. The system count is >32 bits
so the HCTL-2032 / 2032-SC
can be cascaded with other
standard counter ICs to give
absolute position.
CHA
CHB
STATE
4X Decoder
(Count Up & Count Down)
Pulse
Pulse
Pulse
Pulse
1
1
0
0
0
1
1
0
1
2
3
4
Figure 13. 4x Decoder Mode
CHA
CHB
STATE
2x
Count Up
Pulse
-
Pulse
-
2x
Count Down
-
Pulse
-
Pulse
1x
Count Up
Pulse
-
-
-
1x
Count Down
-
Pulse
-
-
1
1
0
0
0
1
1
0
1
2
3
4
Figure 14. 2x and 1x Decoder Modes
相关PDF资料
PDF描述
HCTL-2032-SC Quadrature Decoder/Counter Interface ICs
HCTS00D Radiation Hardened Quad 2-Input NAND Gate
HCTS00HMSR Radiation Hardened Quad 2-Input NAND Gate
HCTS00DMSR Radiation Hardened Quad 2-Input NAND Gate
HCTS00K Radiation Hardened Quad 2-Input NAND Gate
相关代理商/技术参数
参数描述
HCTL-2032-SC 功能描述:接口 - 专用 Decoder/Counter RoHS:否 制造商:Texas Instruments 产品类型:1080p60 Image Sensor Receiver 工作电源电压:1.8 V 电源电流:89 mA 最大功率耗散: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:BGA-59
HCTL-2032-SCT 制造商:Avago Technologies 功能描述:QUADRATURE DECODER/ COUNTER INTRFC IC 32PIN - Tape and Reel
HCT-L-R5A 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic
HCT-L-R5B 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic
HCT-L-R-HA 制造商:未知厂家 制造商全称:未知厂家 功能描述:Optoelectronic