4
Introduction
UC-00-M51 EN R1.0
1.3
Interfaces
RF_IN
LNA
UFirebird II
MEMS
(Gyro, Acc)
Reset
SRAM
GNSS RF
CPU
ROM
GNSS BB
Interface
UM621N
RF Input Matching
Backup Power Supply
RTC
Power Supply
TCXO
Direction Signal
Speed Signal
SAW
UART
1PPS
SPI
I
2
C
Figure 1-1 UM621N Block Diagram
UART
UART1 is the main serial port of UM621N, supporting data transmission and firmware
upgrade, and the signal input/output voltage level is LVTTL. The baud rate can be
configured by users flexibly, and the maximum is 460800bps.
Ensure that UART1 is
connected to a PC or an external processor for firmware upgrade.
UART2 only supports data transmission and can’t be used for firmware upgrade.
MEMS
UM621N integrates a six-axis MEMS, a three-axis gyro and a three-axis accelerator.
MEMS provides information on carrier attitude and speed changes, combined with
GNSS data to output integrated positioning and navigation solution. The combination of
GNSS+MEMS ensures better positioning performance than standalone GNSS, providing
continuous and uninterrupted positioning, especially in the conditions with poor signals,
such as tunnels, underground garages and
urban canyons.
1PPS
UM621N outputs 1PPS with adjustable pulse width and polarity.
1PPS is not for timing application.
nRESET
Active LOW, and the active time should be no less than 10 ms.
