Specifications

23
PCM_OUT
A CMOS output with a weak internal pull-down. Used in the PCM (pulse code modulation)
interface to transmit digitized audio. The PCM interface is shared with the I
2
S interface.
PCM_IN
A CMOS input with a weak internal pull-down. Used in the PCM interface to receive
digitized audio. The PCM interface is shared with the I
2
S interface.
PCM_CLK
A bi-directional synchronous data clock signal pin with a weak internal pull-down. PCMC is
used in the PCM interface to transmit or receive the CLK signal. When configured as a
master, WT32 generates the clock signal for the PCM interface. When configured as a
slave, the PCMC is an input and receives the clock signal from another device. The PCM
interface is shared with the I
2
S interface.
PCM_SYNC
A bi-directional synchronous data strobe with a weak internal pull-down. When configured
as a master, WT32 generates the SYNC signal for the PCM interface. When configured as a
slave, the PCMS is an input and receives the SYNC signal from another device. The PCM
interface is shared with the I
2
S interface.
USB_D+
A bi-directional USB data line with a selectable internal 1.5 k pull-up implemented as a
current source (compliant with USB specification v1.2) An external series resistor is
required to match the connection to the characteristic impedance of the USB cable.
USB_D-
A bi -directional USB data line. An external series resistor is required to match the
connection to the characteristic impedance of the USB cable.
SPI_NCSB
A CMOS input with a weak internal pull-down. Active low chip select for SPI (serial
peripheral interface).
SPI_CLK
A CMOS input for the SPI clock signal with a weak internal pull-down. WT32 is the slave
and receives the clock signal from the device operating as a master.
SPI_MISO
An SPI data output with a weak internal pull-down.
SPI_MOSI
An SPI data input with a weak internal pull-down.
RF
This pin can be used when not using a chip antenna or w.fl connector of the module.