m3005ld STMicroelectronics, m3005ld Datasheet - Page 3

• Manufacturer Part Number: m3005ld
• Description: Remote Control Transmitter
• Manufacturer: STMicroelectronics

REMOTE CONTROL SIGNAL OUTPUT (REMO)
The REMO signal output stage is a push-pull type.
In the HIGH state, a bipolar emitter-follower allows
a high output current. The timing of the data output
format is listed in tables 1 and 2. The information is
defined by the distance t
edges of the flashed pulses or the first edge of the
modulated pulses (see Figure 3). The format of the
output data is given in Figures 2 and 3. The data
word starts with two toggle bits T1 and T0, followed
by three bits for defining the sub-system address
S2, S1 and S0, and six bits F, E, D, C, B and A which
are defined by the selected key.
In the modulated transmission mode the first toggle
bit is replaced by a constant reference time bit
(REF). This can be used as a reference time for the
decoding sequence. The toggle bits function is an
indication for the decoder that the next instruction
has to be considered as a new command. The
codes for the sub-system address and the selected
key are given in tables 3 and 4.
The REMO output is protected against ”Lock-up”,
i.e. the length of an output pulse is limited to < 1ms,
even if the oscillator stops during an output pulse.
This avoids the rapid discharge of the battery that
would otherwise be caused by the continuous ac-
tivation of the LED.
OSCILLATOR INPUT / OUTPUT
(OSCI and OSCO)
The external components must be connected to
these pins when using an oscillator with a ceramic
resonator. The oscillator frequency may vary be-
tween 350kHz and 600kHz as defined by the reso-
nator.
FUNCTIONAL DESCRIPTION
Keyboard operation
In the stand -by mode all drivers (DRV0N to
DRV6N) are on (low impedance to V
a key is pressed, one or more of the sense inputs
(SENnN) are tied to ground. This will start the
power-up sequence. First the oscillator is activated
and after the debounce time t
output drivers (DRV0N to DRV6N) become active
successively.
Within the first scan cycle the transmission mode,
the applied sub-system address and the selected
b
between the leading
DB
(see Figure 4) the
SS
). Whenever
command code are sensed and loaded into an
internal data latch.
In contrast to the command code, the sub-system
is sensed only within the first scan cycle. If the
applied sub-system address is changed while the
command key is pressed, the transmitted sub-sys-
tem address is not altered.
In a multiple key stroke sequence (see Figure 5)
the command code is always altered in accordance
with the sensed key.
MULTIPLE KEY-STROKE PROTECTION
The keyboard is protected against multiple key-
strokes. If more than one key is pressed at the
same time, the circuit will not generatea new output
at REMO (see Figure 5). In case of a multiple
key-stroke, the scan repetition rate is increased to
detect the release of a key as soon as possible.
There are two restrictions caused by the special
structure of the keyboard matrix :
- The keys switching to ground (code numbers 7,
- SEN5N and SEN6N are not protected against
OUTPUT SEQUENCE (data format)
The output operation will start when the selected
code is found. A burst of pulses, including the
latched address and command codes,is generated
at the output REMO as long as a key is pressed.
The format of the output pulse train is given in
Figures 2 and 3. The operation is terminated by
releasing the key or if more than one key is pressed
at the same time. Once a sequence is started, the
transmitted data words will always be completed
after the key is released.
The toggle bits T0 and T1 are incremented if the
key is released for a minimum time t
ure 4). The toggle bits remain unchanged within a
multiple key-stroke sequence.
15, 23, 31, 39, 47, 55 and 63) and the keys
connectedto SEN5N and SEN6N are not covered
completely by the multiple key protection. If one
sense input is switched to ground, further keys on
the same sense line are ignored, i.e. the com-
mand code corresponding to ”key to ground” is
transmitted.
multiple keystroke on the same driver line, be-
cause this condition has been used for the defi-
nition of additional codes (code number 56 to 63).
M3005LAB1 - M3005LD
REL
(see Fig-
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