BCM20706 Data Sheet
Triac Control
Triac Control
The BCM20706 includes hardware support for zero-crossing detection and trigger control for up to four triacs.
The BCM20706 detects zero-crossing on the AC zero detection line and uses that to provide a pulse that is
offset from the zero crossing. This allows the BCM20706 to be used in dimmer applications, as well as any other
applications that require a control signal that is offset from an input event.
The zero-crossing hardware includes an option to suppress glitches.
Serial Peripheral Interface
The BCM20706 has two independent SPI interfaces. One is a master-only interface (SPI_2) and the other
(SPI_1) can be either a master or a slave. Each interface has a 64-byte transmit buffer and a 64-byte receive
buffer. To support more flexibility for user applications, the BCM20706 has optional I/O ports that can be
configured individually and separately for each functional pin. The BCM20706 acts as an SPI master device that
supports 1.8V or 3.3V SPI slaves. The BCM20706 can also act as an SPI slave device that supports a 1.8V or
3.3V SPI master.
Note: SPI voltage depends on VDDO; therefore, it defines the type of devices that can be supported.
Infrared Modulator
The BCM20706 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 BCM20706 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 6 on page 24).
Broadcom®
Bluetooth SoC
May 19, 2016 • 20706-DS202-R
Page 23
BROADCOM CONFIDENTIAL
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