參數(shù)資料
型號(hào)： FCD4B14
廠商： Atmel Corp.
英文描述： Thermal Fingerprint Sensor with 0.4 mm x 14 mm Sensing Area and Digital Output
中文描述： 熱指紋傳感器感光面積和數(shù)字輸出的0.4毫米× 14毫米
文件頁(yè)數(shù)： 12/20頁(yè)
文件大?。?/td> 265K
代理商： FCD4B14
12
FCD4B14
1962C
–
01/02
Analog-to-Digital
Converter/
Reconstructing an 8-bit
Fingerprint Image
An Analog-to-Digital Converter (ADC) is used to convert the analog signal coming from
the pixel into digital data that can be used by a processor.
As the data rate for parallel port and USB is in the range of 1 MB per second and at least
a rate of 500 frames per second is needed to reconstruct the image with a fair sweeping
speed for the finger, two 4-bit ADCs have been used to output 2 pixels at a time on 1
byte.
Start Sequence
A reset is not necessary between each frame acquisition!
Start sequence must consist of:
1.
Set the RST pin to high
2.
Set the RST pin to low
3.
Send 4 clock pulses (due to pipe-line)
4.
Send clock pulses to skip the first frame
Note that the first frame never contains relevant information because the integration
time is not correct.
Figure 8.
Start Sequence
Reading the Frames
A frame consists of 280 true columns + 1 dummy column of 8 pixels. As two pixels are
output at a time, a system must send 281x4 = 1124 clock pulses to read one frame.
Reset must be low when reading the frames.
Read One Byte/Output
Enable
Clock is taken into account on the falling edge and data are output on the rising edge.
For each clock pulse, after the start sequence, a new byte is output on the Do0-3, De0-
3 pins. This byte contains 2 pixels: 4-bit on Do0-3 (odd pixels), 4-bit on De0-3 (even
pixels).
To output the data, the output enable (OE) pin must be low. When OE is high, the Do0-
3 and De0-3 pins are in high impedance state. This enables an easy connection to a
microprocessor bus without additional circuitry-it will enable data output by using a chip
select signal. Note that the FCD4B14 is always sending data: there is no data exchange
to perform using read/write mode.
Power Supply Noise
IMPORTANT: When a falling edge is applied on OE (i.e when the Output Enable
becomes active), then some current is drained from the power supply to drive the 8 out-
puts, producing some noise. It is important to avoid such noise just after the falling edge
of the clock PCLK, when the pixels information is evaluated: the timing diagram figure 5
and time T
NOOE
defines the interval time where the power supply must be as quiet as
possible.
Video Output
An analog signal is also available on pins AVE and AVO. Note that video output is avail-
able one clock pulse before the corresponding digital output (one clock pipe-line delay
for the analog to digital conversion).
1
4
3
1
2
1
1124
Clock PCLK
Reset RST
4+1124 clock pulses to skip the first frame
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
FCD4B14CC 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Thermal Fingerprint Sensor with 0.4 mm x 14 mm Sensing Area and Digital Output
FCD4B14CCB 制造商:ATMEL 制造商全稱:ATMEL Corporation 功能描述:Thermal Fingerprint Sensor with 0.4 mm x 14 mm Sensing Area and Digital Output
FCD4C1690 制造商:n/a 功能描述:Power Semiconductor
FCD4N60 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:600V N-Channel MOSFET
FCD4N60TF 功能描述:MOSFET 600V NCH MOSFET RoHS:否 制造商:STMicroelectronics 晶體管極性:N-Channel 汲極/源極擊穿電壓:650 V 閘/源擊穿電壓:25 V 漏極連續(xù)電流:130 A 電阻汲極/源極 RDS（導(dǎo)通）:0.014 Ohms 配置:Single 最大工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:Max247 封裝:Tube
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