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参数资料
| 型号： | PCA84C122BT |
| 厂商： | NXP SEMICONDUCTORS |
| 元件分类： | 微控制器/微处理器 |
| 英文描述： | 8-bit microcontrollers for remote control transmitters |
| 中文描述： | 8-BIT, MROM, 3 MHz, MICROCONTROLLER, PDSO20 |
| 封装： | 7.50 MM, PLASTIC, SOT-163-1, SO-20 |
| 文件页数： | 6/24页 |
| 文件大小： | 142K |
| 代理商： | PCA84C122BT |
1995 May 01
14
Philips Semiconductors
Product specication
8-bit microcontrollers for
remote control transmitters
PCA84C122; 222; 422; 622; 822
15 APPLICATION INFORMATION
Fig.12 PCA84C122A Remote control transmitter application.
P10
P00
P11
P01
P12
P02
P13
P03
P14
P04
P15
P05
P16
P06
P17
P07
84C122A
T1
RESET
V
DD
XTAL2
XTAL1
VSS
MCD252
100
27 mA
3.0 V
T0 / INT
OUT
Figure 12 shows the main application of the PCA84C122
as a remote control transmitter. Each key of the transmitter
keypad represents a specific command. The keys are in an
orderly matrix with each key connected between an I/O
line of Port 0 and an I/O line of Port 1.
The lines of Port 0 are designated ‘scan’ (output) lines, and
the lines of Port 1 are ‘sense’ (input) lines.
By making each scan line a logic 0 in turn, and each time
looking at the sense lines, the depressed key is detected.
The corresponding command code is determined by using
a software look-up table. This code together with the
system address is sent according to a coding scheme or
protocol (e.g. RC-5). The pulses that are generated are
available at the OUT pin. This pin drives the output
transistor, which provides the current for the IR-LED.
T0/INT is not used and therefore connected to VDD. T1 is
used for system or option selection, therefore a jumper can
be connected to VDD or ground.
When more options must be selected, this can be done in
different ways as illustrated in the following two examples:
1. When the number of keys is sufficiently low a scan line
can be spared. This scan line may be used to connect
a jumper wire to one of the sense lines. Normally the
scan line should be logic 1. When this line is set to
logic 0 the option setting can be read from the sense
lines.
2. By connecting diodes between one sense line and a
number of scan lines (see Fig.12). If necessary these
diodes can be placed parallel to the keys. When the
sense line is set to logic 0 (acts as scan line), the
option setting can be read from the scan lines (which
act as sense lines and should be set to logic 1
beforehand).
For the oscillator a crystal or ceramic resonator may be
used. A resistor in series with the supply, limits the reverse
current through the IC in the event of the supply voltage
being reversed (i.e. wrong insertion of batteries).
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相关代理商/技术参数 |
参数描述 |
|---|---|
| PCA84C222 | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:8-bit microcontrollers for remote control transmitters |
| PCA84C222A | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:8-bit microcontrollers for remote control transmitters |
| PCA84C222AP | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:8-bit microcontrollers for remote control transmitters |
| PCA84C222AT | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:8-bit microcontrollers for remote control transmitters |
| PCA84C222B | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:8-bit microcontrollers for remote control transmitters |
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