Ublox BMD-34 EVK Series User Manual

Also see for BMD-34 EVK Series: User guide User guide

Contents

Ublox BMD-34 EVK Series User Manual Manual pdf 10 page image

BMD-34 EVK - User guideUBX-19033356 - R03 Hardware description Page 10 of 202.5 Virtual COM portThe evaluation board allows for easy serial communication with the BMD-34 series modulesand a connected computer. The Interface IC provides a virtual COM port USB device thatconnects to four GPIO pins on the module, allowing for UART communication with or withouthardware flow control. The UART lines can be completely removed from the circuit by breakingthe associated jumpers.BMD-34 Pin Name BMD-34 Function Jumper Interface IC FunctionP0.05 RTS J05 CTSP0.06 TXD J06 RXDP0.07 CTS J07 RTSP0.08 RXD J08 TXDTable 2: Virtual COM port2.6 32 kHz crystal oscillatorThe evaluation board has a 32.768 kHz crystal oscillator connected to the BMD-34 module bydefault. This allows the module to use any of the three available low frequency (LF) clocksources: an internal calibrated RC oscillator, an internal synthesized clock (derived from the32 MHz clock), or an external crystal oscillator. The external crystal oscillator is the mostaccurate and lowest power LF clock option. For applications without strict time keepingrequirements, the internal calibrated RC oscillator is often suitable. The crystal is connectedto the module through a solder select jumper, allowing either the crystal or the IO header to beconnected to the module’s GPIO pins.Figure 7: Schematic – 32 kHz crystal2.7 NFC connectorConnection to an external NFC antenna is provided through a Molex flat-flex connector, Partnumber 051281-0594. Capacitors “C2” and “C3” provide tuning of the NFC antenna forresonance at 15.56 MHz.Figure 8: NFC connector