3
1.3
Interfaces
RF_IN
LNA
UFirebird
MEMS
（
Gyro
，
Acc
）
UART
RST
SRAM
GNSS RF
CPU
ROM
GNSS Baseband
Interface
UM220-INS NF
Vbackup
RTC
VCC
1PPS
TCXO
FWD
WHEEL TICK
SAW
Figure 1-2 Structure
UART
UM220-INS NF module support 2 configurable UART ports, the signal input/output level is LVTTL. The
default baud rate is 9600bps, and is adjustable, can be configured up to 115200bps.
COM1 is the primary serial port, which supports data transfer and firmware upgrade function.
During design in, please ensure that COM1 is connected to a PC or an external processor for
firmware upgrades.
For routine starts of the module, please keep COM1 ‘s input pin at a constant high or constant low
level 1 second after the reset signal goes high.
COM2 only supports data transmission, and can’t be used for firmware upgrade purpose, reserved for
future use.
Odometer (FWD/WHEELTICK)
The UM220-INS NF module has an odometer input interface that includes FWD and WHEELTICK, which
are useful for improving the module’s location accuracy.
MEMS
UM220-INS NF integrated sis axis MEMS on board, 3 axis gyro and 3 axis accelerator. MEMS provide
vehicle dynamic changing info and UM220-INS NF combine them with GNSS calculation and output
the inertial positioning result directly. This combination ensures the positioning experience for users,
much more continuous than the pure GNSS module, especially under GNSS signal loss scenario such
as tunnels
and underground parking.
