JPH09139987A5 - - Google Patents

Description

[Title of Invention] Video recorder control method and video recorder

[0001]
[Technical Field to which the Invention Belongs]
The present invention relates to a method for controlling a video recorder and to a video recorder .

[0009]
[Problem to be solved by the invention]
Therefore, the object of the present invention is to provide a suitable remote control for a VCR, TV or GEMSTAR that allows for simple circuitry and a convenient user interface. A method for controlling a video recorder such as a G-Code/Showview unit and a video recorder are provided.

[0023]
[Embodiments of the Invention]
As shown in FIG. 1, a learning remote control device, which may be built-in to a video recorder such as a video cassette recorder ( VCR ), television unit, GEMSTAR unit, or which may be part of a remote control unit , comprises a photodiode circuit 1, an IR module 2 which is preferably an existing part of the video recorder , an IR transmitting circuit 3, a microcontroller 4, and a memory 5, such as an EEPROM, which is also an existing part of the video recorder .

[0025]
In general, the method for learning an IR code may include the following steps:
a) detecting whether the incoming signal is of pulsed or modulated type;
b) detecting whether the incoming signal has a toggle bit;
c) detecting a data code;
d) detecting the transmission format;
d) Check the learned code and format.
The method preferably begins with step a and ends with step e, although the order of steps b, c, and d can be changed. Typically, the photodiode circuit is first activated by appropriate settings of the switching means, so that the pulse width or carrier period is first detected.
The carrier period is detected in the following way:
When the first low signal arrives, a timer is started, which counts down for a predetermined period T, preferably 250 μs, a register W is incremented every time interval t (t<T) for a low signal, preferably every t=8 μs, and another register A is incremented every time interval t for a high signal, preferably every t=8 μs, and when a transition from high to low occurs, both registers W and A are cleared, while another register C is incremented, so that after a time interval T+t _{(t 0 ≪T} ), preferably after (T+t ₀ )=255 μs, a timer interrupt is generated and the period of the carrier wave is calculated from the following formula:
Period = (T - (W + A) x t) / C [to the nearest unit]
According to the result, it is determined whether the incoming IR signal is of carrier type or pulse type, and then the switching means is set to the photodiode circuit when the incoming IR signal is identified as pulse type, and is set to the IR module when the incoming IR signal is identified as carrier type.
In this way, the data to be stored in the memory is advantageously compressed, thereby saving memory space.
To achieve data compression , identical timing sets consisting of high and low timings are grouped together so that only one set of data is stored with the corresponding IR timing data pointer. In other words, the same code set (timing set) is stored only once, because each pointer carries information about how many times the set must be repeated.
Furthermore, the method has a user interface for implementing it, whereby the stages of the learning procedure, i.e. steps a to e, are displayed on a TV screen.
Next, a specific description will be given with reference to FIGS.
FIG. 3 shows a method for acquiring and detecting the carrier frequency of an incoming IR signal. To learn the incoming IR code, photodiode circuit 1 is first activated. If present, switching circuit 6 is set to transmit only signals from photodiode circuit 1 to microcontroller 4. When a user presses a key on their remote control unit 7 (RCU), the learning remote's software detects whether the IR signal is a pulse or carrier type. At the same time, the software detects the pulse width (if pulse type) or the carrier period (if carrier type). The method for detecting the carrier period is shown in FIG. 3. When the first low signal arrives, a timer is started. The timer counts down for 250 μs. A register, e.g., REG_W, is incremented every 8 μs for a low signal, and another register, e.g., REG_A, is incremented every 8 μs for a high signal. When a high to low transition occurs, both registers W and A are cleared while another register C is incremented. After 255 μs, a timer interrupt occurs. The period of the carrier wave is then calculated from the following formula:
Period = (255μs-(W+A)×8μs)/C
If the IR signal is of pulse type, the software that examines the high and low signals detects the length of the pulse width. Next, the operation of the learning control device will be described. If the IR signal is of carrier type, then the software sets the switching unit 6 so that only the signal captured by the IR module passes to the microprocessor 4. In the first embodiment, this switching unit is realized by the microprocessor 4 itself. The carrier wave of the IR signal is filtered when passing through the IR module, so that only the envelope of the IR signal is detected. The timing of the IR signal code is then stored in the RAM 5 of the microprocessor 4 in the form of duplex data.

[0036]
Step 2: Toggle bit detection ( c in FIG. 4)
In this step, the user is required to press the numeric "1" key on their remote controller 7 three or more times. A first set of numeric "1" data is compared with a second set of numeric "1" data to check whether any bits are toggled. If more than two bits differ, the resulting data is deemed erroneous and therefore discarded. The first and second sets are then recaptured. If the two sets of data differ by two bits or less, a third set will be used to verify the toggle bit location and timing data. If any errors in the third set are detected (e.g., the toggle bit locations do not match), then the entire procedure of step 2 is repeated. The screen display for capturing the numeric "1" signal is the same as in step 1.

[0037]
Stage 3: Learning numbers ( d in Figure 4)
After learning the number "1" on the user's RCU, learning another number on the RCU begins. The number (e.g., "2") after the word "press" will flash to prompt the user to press the indicated number (=press 2). After capturing the number signal, the flashing will stop and the line "Decoding..." will appear at the bottom of the screen. The line "1234567890" will be highlighted up to the just-captured number. The captured code will then be stored in the EEPROM.

[0038]
Step 4: Transmission format learning ( e in FIG. 4)
Some IR signals have special formats, some of which are listed below:
1. Mode with 'ENTER' key: The ENTER key should be sent after the number to fix the channel setting.

[0043]
Step 5: Checking the Learned Code At this step the user can check whether the code has been learned correctly. The user selects the two numbers he wants to check the RCU with using the VCR. The software then reproduces the stored data codes and sends them out via the transmission circuit 7 (Fig. 1).

[Brief explanation of the drawings]
FIG. 1 is a block diagram of an example learning remote control device.
FIG. 2 is a block diagram of another example learning remote control device.
FIG. 3 is a diagram illustrating a method for detecting a carrier frequency.
FIG. 4 illustrates a user interface for built-in learning remote control on a VCR.
[Explanation of symbols]
1 Photodiode circuit, 2 IR module, 3 IR transmitter circuit, 4 Microcontroller, 5 Memory, 6 Switching circuit, 7 Remote control unit or remote controller (RCU)

Claims (5)

1. A method for controlling a video recorder, comprising:
a) prompting the user to press a key on the satellite/cable box remote control unit (7);
b) receiving a signal coming from a remote control unit (7) via the infrared receiving means (1, 2) of the video recorder;
c) determining a data code of the incoming signal;
d) The data code is stored in a memory means (5) of the video recorder.
A method consisting of steps. e) Retrieving said data code from said memory means (5);
f) Transmitting a signal based on said data code to said satellite/cable box via an infrared transmitting means (3) of the video recorder.
Further comprising the steps
The method of claim 1. said step a) being carried out on a screen connected to a video recorder;
3. The method according to claim 1 or 2. means for prompting a user to press a key on the satellite/cable box remote control unit (7);
Infrared receiving means;
means for determining a data code of the signal received by the infrared receiving means;
memory means (5) for storing said data code;
A video recorder comprising: and infrared transmitting means (3) capable of transmitting a signal to a satellite/cable box based on the data code retrieved from said memory means (5).
5. The video recorder according to claim 4.