BCM20730 Data Sheet
Infrared Modulator
The BCM20730 can provide up to four synchronized control signals for left and right eye shutter control. These
four lines can output pulses with microsecond resolution for on and off timing. The total cycle time can be set
for any period up to 65535 msec. The pulses are synchronized to each other for left and right eye shutters.
The BCM20730 seamlessly adjusts the timing of the control signals based on control messages from the
BCM20702, ensuring that the 3D glasses remain synchronized to the TV display frame.
3D hardware control on the BCM20730 works independently of the rest of the system. The BCM20730
negotiates sniff with the BCM20702 and, except for sniff resynchronization periods, most of the BCM20730
circuitry remains in a low power state while the 3D glasses subsystem continues to provide shutter timing and
control pulses. This significantly reduces total system power consumption.
The BCM20730A2 has the new BT SIG 3DG profile, as well as legacy mode 3DG, included in ROM. This allows it
to support a smaller and lower cost external memory of 4 KB.
Infrared Modulator
The BCM20730 includes hardware support for infrared TX. The hardware can transmit both modulated and
unmodulated waveforms. For modulated waveforms, hardware inserts the desired carrier frequency into all IR
transmissions. IR TX can be sourced from firmware-supplied descriptors, a programmable bit, or the peripheral
UART transmitter.
If descriptors are used, they include IR on/off state and the duration between 1–32767 µsec. The BCM20730
IR TX firmware driver inserts this information in a hardware FIFO and makes sure that all descriptors are played
out without a glitch due to underrun. See Figure 2.
Figure 2: Infrared TX
BROADCOM
®
September 9, 2013 • 20730-DS108-R
Page 14
BROADCOM CONFIDENTIAL
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