Data Sheet

UM7 DATASHEET
Rev. 1.6 – Released 1/10/2016
14
IO EXPANSION HEADER
Mating connector: JST part number ZHR-6(P)
Pin Name
Description
TX2
Secondary UART TX output (3.3V TTL). Can be used
to interface with external GPS or Bluetooth module.
If connected to GPS, this pin can serve as the PPS
input to synchronize the system clock with UTC time
(configured in the CREG_MISC_SETTINGS register).
Leave unconnected if not used.
RX2
Secondary UART RX input (3.3V TTL). Can be used to
interface with external GPS or Bluetooth module.
Leave unconnected if not used.
MOSI
SPI interface MOSI pin (3.3V TTL). Leave
unconnected if not used.
MISO
SPI interface MISO pin (3.3V TTL). Leave
unconnected if not used.
SCK
SPI interface clock (3.3V TTL). Leave unconnected if
not used.
SS
SPI interface slave-select pin (3.3V TTL). Leave
unconnected if not used.
PROGRAMMING HEADER
Mating connector: JST part number ZHR-6(P)
Pin Name
Description
DIO
Pin for factory programming. Leave unconnected if
not used.
CLK
Pin for factory programming. Leave unconnected.
RST
Pin for factory programming. Leave unconnected.
3.3V
3.3V out
GND
Supply GND
BT0
Boot0 pin. Short this pin to +3.3V pin before
powering the device to activate bootloader for
firmware programming.