D6122G NEC, D6122G Datasheet - Page 14

• Manufacturer Part Number: D6122G
• Description: Search -----> UPD6122G
• Manufacturer: NEC

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7. ONE-SHOT/CONTINUOUS COMMAND TRANSMISSION MODE
7.1 One-shot Command Transmission Mode
once, and thereafter transmit just the leader code and stop bit indicating that a key is depressed. As a result,
this transmission method (one-shot command transmission mode) has the following characteristics.
Advantages
• Average transmission current is reduced to 1/3 to 1/4 compared with continuous command transmission mode
• Reduced software load for reception program (not all commands are processed all the time)
• This mode distinguishes when a key is pressed several times successively and when a key is kept depressed.
Disadvantages
• If a command is not read the first time, it cannot be read a second time
• If a signal transmission is interrupted while continuous commands are executed, subsequent commands cannot
3 % of the peak current.
7.2 Continuous Command Transmission Mode
output lines simply by adding a diode D and connecting it to KI
peak current.
14
In order to reduce the average transmission current, the PD6120C, 6121G, and 6122G transmit data only
be executed.
Moreover, when f
I
A continuous command transmission mode for transmitting data a second or more times is also available.
As shown in Figure 7-2, it is possible to continuously transmit commands for all the keys or for individual key
In this case, the average transmission current is larger than that in the one-shot command transmission mode.
When f
I
Cautions 1. If the double input key (K21-K24) is used in the continuous command transmission mode,
Figure 7-1 shows the continuous command transmission mode.
AVE
AVE
= (9 ms + 0.56 ms)/108 ms x 1/3 (duty) = 2.95 % (first command is ignored)
= (9 ms + 0.56 ms x 33)/108 ms x 1/3 (duty) = 8.48 %
OSC
2. When the voltage drop of the REM output is large, the signal is not transmitted accurately.
= 455 kHz, the average current to the infrared-emitting diode is roughly equivalent to 9 % of the
double-input key transmission is not performed (D
Therefore, keep the REM output current within 1 mA.
OSC
= 455 kHz, the average current to the infrared-emitting diode is roughly equivalent to
0
or KI/O.
5
does not become 1).
PD6121, 6122