UNICORECOMM UM982-EB User manual

HARDWARE
USER MANUAL
WWW.UNICORECOMM.COM
Copyright© 2009-2022, Unicore Communications, Inc.
Data subject to change without notice.
UM982-EB
Evaluation Board

i
Revision History
Version
Revision History
Date
P1.0.3
Draft
2022-10-26
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UM982-EB User Manual
ii
Should you purchase our product and encounter any inconsistency, please contact us or
our local authorized distributor for the most up-to-date version of this manual along
with any addenda or corrigenda.

iii
Foreword
This manual provides information on the hardware composition and design of the UM982
evaluation board (EB).
Target Readers
This document is written for technicians who are familiar with GNSS modules.

UM982-EB User Manual
I
Contents
1Product Overview ......................................................................................... 1
2Interfaces...................................................................................................... 4
3Power Supply ............................................................................................... 6
3.1 3.3V LDO Power Supply ..................................................................................................7
3.2 5V DC/DC Power Supply .................................................................................................8
3.3 Backup Power Supply......................................................................................................9
4Antenna circuit ........................................................................................... 10
4.1 Antenna Short Protection Circuit..................................................................................10
4.2 Antenna Feed Circuit .....................................................................................................11
5LED Indicators ............................................................................................ 12
6UM982 Peripheral Design .......................................................................... 13
7Debug Support ........................................................................................... 15
Appendix ........................................................................................................... 16

UC-08-M31 EN P1.0.3 Product Overview 1
The schematic of the UM982-EB can be used as the reference design for the
UM982 module.
UM982-EB
UM982
ANT_IN
VBCKP
PPS
COM3
EVENT
PVT
ERR
RTK
I2C
COM1
SPIS
COM2
RSTN
BAT
Dual-row pins
Dual-row pins
VCC 5V
DC/DC
Antenna
protection
circuit
5V
LDO 3V3
Antenna
protection
circuit
ANT_IN
Figure 1-1 UM982-EB Block Diagram
1 Product Overview
UM982-EB is the evaluation board for UM982 and it consists of the UM982 module,
a 3.3 V low dropout regulator (LDO), a 5V DC/DC boost circuit, two antenna short
protection circuits and peripheral interfaces.

UM982-EB User Manual
2 Product Overview UC-08-M31 EN P1.0.3
The appearance of UM982-EB is shown as follows:
1
2
3
4
Figure 1-2 Top View of UM982-EB
(1) Silkscreen: It marks the signals of the pins. The smaller holes around are used to
mount the UM982 socket. The printing adopts exposed copper to ensure the
flatness of the surface.
(2) UM982 module: The pin pads are designed long, which is convenient for soldering,
testing and debugging. For detailed packaging information, please refer to the
PCB document.
(3) PPS connector: To measure the PPS signal, solder an MMCX connector here.
(4) LED indicators: Indicating the status of the power supply, reset, antenna short
circuit, the positioning status and UART.

UC-08-M31 EN P1.0.3 Product Overview 3
3
2
5
6
7
7
8
8
4
1
1
Figure 1-3 Bottom View of UM982-EB
(1) Antenna short protection circuit
(2) Anti-static design and heat dissipation with exposed copper
(3) VCC power supply and LDO circuit
(4) Backup battery
(5) 5 V DC/DC boost circuit for antenna feeding
(6) Dual-row pins as external interfaces
(7) Debug ports
(8) Ports used to connect jumpers

UM982-EB User Manual
4 Interfaces UC-08-M31 EN P1.0.3
2Interfaces
The dual-row 28 pins serve as the external interfaces of UM982-EB, and the pin pitch is
2 mm. The interfaces can be directly connected to the J18 on Unicore HPL EVK-V5.0
board.
J6
CH71283V100
Figure 2-1 UM982-EB Interfaces
Table 2-1 UM982-EB Pin Description
No.
Pin Name
I/O
Description
1
SPIS_MOSI
I
Master Out / Slave In. This pin is used to receive
data in slave mode.
2
SPIS_CSN
I
Chip select pin for SPI slave
3
SPIS_CLK
I
Clock input pin for SPI slave
4
SPIS_SDRY
O
Interrupt output of SPI slave
5
LNA_PWR
I
Antenna feed voltage for LNA
6
VIN
I
Main power supply
7
SPIS_MISO
O
Master In / Slave Out. This pin is used to
transmit data in slave mode.
8
RXD3
I
COM3 input, can be used as CAN RXD, LVTTL

UC-08-M31 EN P1.0.3 Interfaces 5
No.
Pin Name
I/O
Description
9
RESET_N
I
System reset, active low, and the active time
should be no less than 5 ms.
10
RSV#12
—
Reserved
11
EVENT
I
Event mark input, with adjustable frequency
and polarity
12
RSV#29
—
Reserved
13
TXD3
O
COM3 output, can be used as CAN TXD, LVTTL
14
GND
—
Ground
15
TXD1
O
COM1 output, LVTTL
16
RXD1
I
COM1 input, LVTTL
17
GND
—
Ground
18
TXD2
O
COM2 output, LVTTL
19
RXD2
I
COM2 input, LVTTL
20
GND
—
Ground
21
PVT_STAT
O
PVT status, active high.
High level when positioning and low level when
not positioning.
22
GND
—
Ground
23
PPS
O
Pulse per second, with adjustable pulse width
and polarity
24
RSV#31
—
Reserved
25
RTK_STAT
O
RTK status, active high.
High level for RTK fixed solution and low level
for other status.
26
ERR_STAT
O
Error status, active high.
High level when failing self-test and low level
when passing self-test.
27
SDA
I/O
I2C data
28
SCL
I/O
I2C clock

UM982-EB User Manual
6 Power Supply UC-08-M31 EN P1.0.3
The availability of the ports depends on the firmware version of the UM982 module.
3Power Supply
The power supply of the UM982-EB is input from the VIN pin, passing through a circuit
with surge protection and filter capacitors, to provide power for the 3.3 V LDO circuit and
5 V DC/DC boost circuit.
The input range of VIN is 3.2 V to 5 V.
VIN operation range: 3.2 V ~ 5 V
FC1
NFM21PC104R1E3D
Figure 3-1 Power Filter Circuit
Figure 3-2 3.3 V LDO and 5 V DC/DC on the Bottom of UM982-EB
3.3V LDO
5V DC/DC

UC-08-M31 EN P1.0.3 Power Supply 7
3.1 3.3V LDO Power Supply
VCC outputs 3.3 V voltage after passing through the LDO circuit to provide power to
UM982-EB.
Vout=0.8*(1+16/5.1)=3.31V
Dropout Voltage: 170mV@1A
0805
0805
U3
TPS7A8101DRB
Figure 3-3 3.3V LDO Circuit
Notes:
The rated output current of LDO should be more than twice the maximum operating
current of UM982.
R32 is a series resistor placed at the input of the LDO, which is used for debugging. When
selecting the resistor, choose one with high rated power to ensure the current capability.
Here, a 0805 0-ohm resistor is selected.
R33 is a resistor connected in parallel with LDO. After removing R32 and soldering R33,
you can use VCC to power the module.

UM982-EB User Manual
8 Power Supply UC-08-M31 EN P1.0.3
3.2 5V DC/DC Power Supply
VCC outputs 5 V voltage after passing through the DC/DC boost circuit to feed the
antenna.
Vout=1.225*(1+16/5.1)=5.07V
U4
LT3467AIDDB
Figure 3-4 5V DC/DC Boost Circuit
Note:
You can choose whether to use the 5 V power on the board to feed the antenna according
to the antenna type.
R59 and R74 are series resistors connected to the DC/DC circuit at the input and output,
which are used for debugging. When selecting the resistors, choose those with suitable
rated power according to the power consumption of the antenna load. Here a 0603 0-ohm
resistor is selected.
R78: After removing R59/R74 and soldering R78, you can use the external LNA_PWR to
feed the antenna.

UC-08-M31 EN P1.0.3 Power Supply 9
3.3 Backup Power Supply
When using the hot start function of UM982, you need to provide backup power for the
module.
The input range of V_BCKP is 2.0 V to 3.6 V.
BT1
MS621T-FL11E
Figure 3-5 Backup Power Circuit
Figure 3-6 Backup Power Circuit on the Bottom of UM982-EB
Note:
The power supply for V_BCKP can be provided by the backup battery. The circuit that
charges the backup battery should be designed to prevent reverse current to ensure that
the battery only supplies power to V_BCKP and the current does not flow back into the
3.3 V power domain, as the D64 shows in Figure 3-5.
According to the maximum charging current of the battery, a current-limiting resistor
should be added, as the R86 shows in Figure 3-5.
V_BCKP can also be powered through the test point TP10. Removing R86, connecting a
power supply wire at TP10 and a ground wire at TP7, you can use an external power to
supply V_BCKP. This method can be used to measure the supply voltage and current of

UM982-EB User Manual
10 Antenna circuit UC-08-M31 EN P1.0.3
V_BCKP.
4Antenna circuit
4.1 Antenna Short Protection Circuit
The antenna short protection circuit consists of a load management chip and peripheral
circuits.
The 5 V power source supplies the antenna after passing through the load management
chip.
When the current of the antenna circuit is greater than 100 mA, it will trigger short circuit
protection, and FLAGB will output low level signals.
Removing R88/R77 (or R7/R6) and soldering R79 (or R8), you can feed ANT1 (or ANT2)
bypassing the short protection circuit.
Ant1 Bias
Ant2 Bias
U2 FPF2004
U5 FPF2004
Figure 4-1 Antenna Short Protection Circuit

UC-08-M31 EN P1.0.3 Antenna circuit 11
Ant1
Ant2
J7
J5
Figure 4-3 Antenna Feed Circuit
Figure 4-2 Antenna Short Protection Circuit on the Bottom of UM982-EB
4.2 Antenna Feed Circuit
The antenna feed circuit consists of the anti-reverse current design, anti-surge design,
filter inductors, and ESD protection.
Removing R77 and R6 and soldering R79 and R8, you can directly use the 5 V power to
supply the antenna. In this condition, the antenna short protection circuit on UM982-EB
will be bypassed.
The ESD protection diode should support high-frequency signal (above 2000 MHz).
Nexperia PESD5V0F1BL is recommended here.

UM982-EB User Manual
12 LED Indicators UC-08-M31 EN P1.0.3
Figure 4-4 Antenna Feed Circuit on the Bottom of UM982-EB
5LED Indicators
There are LED indicators on UM982-EB to indicate the working status of each functional
unit.
Figure 5-1 LED Indicators

UC-08-M31 EN P1.0.3 UM982 Peripheral Design 13
Table 5-1 Description of the LED Status
LED Indicator
Color
Description
Power (5V or 3.3V)
Green
Light on when the power is normal
Reset
Red
Light on when pressing the reset button
Antenna
Red
Light on when antenna is shorted
PVT
Green
Light on when position is fixed
RTK
Green
Light on when RTK is fixed
ERR
Red
Light on when failing self-test
UART
Green
Blinking when UART is working
The silkscreen markings on the right of the LED indicators identify the corresponding
function, as shown in the figure below:
Figure 5-2 Markings on the Right of the LED Indicators
6UM982 Peripheral Design
TVS anti-surge protection is added at the input of the UM982 module. ESD protection is
added at all pins.
Use large and small VCC filter capacitors together, with a total capacitance greater than
30 uF.
Add series resistors at the IO pins for the convenience of debugging.

UM982-EB User Manual
14 UM982 Peripheral Design UC-08-M31 EN P1.0.3
VCCIN powers the UM982 module only. R27 is a large-size resistor (with high rated power)
to ensure the current capability. In the figure below, a 0805 resistor is used.
Removing R27, connecting a power supply wire at TP1 and a ground wire at TP3 (as
shown in Figure 7-1), you can use an external power to supply the module. This method
can be used to measure the input voltage and current of UM982.
0805
U1A UM982
Figure 6-1 UM982 Peripheral Design
Silkscreen markings are printed around the UM982 module to identify the resistors, which
is convenient for measurement.
Figure 6-2 UM982 Peripheral Circuit
The GND pads at the bottom of the module should be grounded to ensure heat dissipation.

UC-08-M31 EN P1.0.3 Debug Support 15
The UM982-EB has copper exposed on the bottom of the UM982 module, which not only
enhances heat dissipation, but also provides a large area for grounding and is convenient
to test.
U1B
UM982
Figure 6-3 UM982 Pads (Y1-Y39) and Socket Mounting Holes (X1-X8)
7Debug Support
As mentioned above, TP1 and TP10 can be used to connect an external power to supply
VCCIN and V_BCKP and to measure the supply voltage and current.
TP2, TP4, TP6 and TP8 are used for internal debugging, of which TP6 and TP8 can be
used to debug I2C.
J1 and J2 are used for MMCX connection. After soldering the MMCX connector, it can be
used to measure the PPS signals.
J3, J4, J8 and J9 are debug ports. Connect the signal that needs to be tested to the square
hole and test the round hole, or connect the round hole to a measuring instrument. Using
these debug ports can avoid damage to the PCB pads and traces, which is convenient for
debugging.