unicore UM980eb Instructions for use

HARDWARE
USER MANUAL
WWW.UNICORECOMM.COM
Copyright© 2009-2023, Unicore Communications, Inc.
Data subject to change without notice.
UM980eb
Evaluation Board

i
Revision History
Version
Revision History
Date
R1.0
First release
Dec. 2023
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purchase.

UM980eb 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 UM980eb
(evaluation board).
Target Readers
This document is written for technicians who are familiar with GNSS modules.

UM980eb 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 Detection Circuit .............................................................................................10
4.2 Antenna Feed Circuit .....................................................................................................12
5LED Indicators........................................................................................................ 13
6UM980 Peripheral Design....................................................................................... 14
7Debug Support....................................................................................................... 16
Appendix....................................................................................................................... 17

UC-08-M32 EN R1.0 Product Overview 1
1Product Overview
UM980eb is the evaluation board for UM980 and consists of the UM980 module, a 3.3V
low dropout regulator (LDO), a 5V DC/DC boost circuit, an antenna detection circuit and
peripheral interfaces.
The schematic of the UM980eb can be used as the reference design for the UM980
module.
UM980eb
UM980
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
detection
circuit
5V
LDO 3V3
Figure 1-1 UM980eb Block Diagram

UM980eb User Manual
2 Product Overview UC-08-M32 EN R1.0
The appearance of UM980eb is shown as follows:
3
2
1
4
Figure 1-2 Top View of UM980eb
(1) Silkscreen: It marks the signals of the pins. The smaller holes around are used
to mount the UM980 socket. The printing adopts exposed copper to ensure the
flatness of the surface.
(2) UM980 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-M32 EN R1.0 Product Overview 3
321
5
6 7
7
8
48
Figure 1-3 Bottom View of UM980eb
(1) Antenna detection 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

UM980eb User Manual
4 Interfaces UC-08-M32 EN R1.0
2Interfaces
The dual-row 28 pins serve as the external interfaces of UM980eb, and the pin pitch is 2
mm. The interfaces can be directly connected to the J18 on Unicore HPL EVK-V5.0
board.
J4
CH71283V100
Figure 2-1 UM980eb Interfaces
Table 2-1 UM980eb 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
NC
—
No connection inside
5
LNA_PWR
I
Antenna feed voltage for LNA
6
VIN
I
Main power supply

UC-08-M32 EN R1.0 Interfaces 5
No.
Pin Name
I/O
Description
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
9
RESET_N
I
System reset, active low. The active time
should be no less than 5 ms.
10
NC
—
No connection inside
11
EVENT
I
Event input, with adjustable frequency and
polarity
12
RSV#22
—
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

UM980eb User Manual
6 Power Supply UC-08-M32 EN R1.0
No.
Pin Name
I/O
Description
24
RSV#23
—
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
The availability of the ports depends on the firmware version of the UM980 module.
3Power Supply
The power supply of the UM980eb 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 3.2V to 5V.
FC1
NFM21PC104R1E3D
VIN operation range: 3.2V~5V
Figure 3-1 Power Filter Circuit

UC-08-M32 EN R1.0 Power Supply 7
Figure 3-2 3.3 V LDO and 5 V DC/DC on the Bottom of UM980eb
3.1 3.3V LDO Power Supply
VCC outputs 3.3 V voltage after passing through the LDO circuit to provide power to
UM980eb.
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 current of UM980.
R38 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.
R39 is a resistor connected in parallel with LDO. After removing R38 and soldering R39,
you can use VCC to power the module.
3.3 V LDO
5 V DC/DC

UM980eb User Manual
8 Power Supply UC-08-M32 EN R1.0
When using the LDO to power the module, you should consider the power dissipation of
the LDO.
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
U5
LT3467AIDDB
Figure 3-4 5V DC/DC Boost Circuit
Notes:
You can choose whether to use the 5 V power on the board to feed the antenna
according to the antenna type.
R61 and R76 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.
R77: After removing R61/R76 and soldering R77, you can use the external LNA_PWR to
feed the antenna.

UC-08-M32 EN R1.0 Power Supply 9
3.3 Backup Power Supply
When using the hot start function of UM980, 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 UM980eb
Notes:
When the backup battery supplies power to V_BCKP, the battery charging circuit 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 D52
shows in Figure 3-5.
According to the maximum charging current of the battery, a current-limiting resistor
should be added, as the R84 shows in Figure 3-5.
V_BCKP can also be powered through the test point TP9. Removing R85, connecting a
power supply wire at TP9 and a ground wire at TP6, you can use an external power to
supply V_BCKP. This method can be used to measure the supply voltage and current of

UM980eb User Manual
10 Antenna Circuit UC-08-M32 EN R1.0
V_BCKP.
In the case of normal power supply to the evaluation board, the micro battery charging
circuit on the board will automatically charge the micro battery.
If the evaluation board has been placed for a long time, the power of the battery may be
low and the hot start test may fail. Therefore, it is recommended to charge the board as
long as possible before testing the hot start function.
1) Use a multimeter to measure the voltage of the micro battery. If the voltage is above 2.6 V
and is stable, it indicates that the power of the micro battery is sufficient.
2) Use a multimeter to measure the voltage of the micro battery. If the voltage drops rapidly, it
indicates that the power of the micro battery is insufficient.
3) When the micro battery runs out of power, it will take more than 96 hours to fully charge the
battery.
4) Under normal circumstances, after powering the evaluation board for one night, the hot start
test can be done normally the next day.
4Antenna Circuit
4.1 Antenna Detection Circuit
The antenna detection circuit consists of a MOS switch, a current detection chip and
two buffers.
The antenna feed supply can be selected from the 5 V DC/DC circuit output or VCC_RF
(supplied by the module). VCC_RF provides 3.3 V voltage, but the circuit has less
protective design; therefore, it is not recommended to use VCC_RF to supply power to
the antenna.
U6 and U2 are two buffers with open-drain output. ANT_OFF1 needs to be pulled up
through ANT_BIAS1 to make sure that MOS can be turned off.
The current threshold can be adjusted by changing the resistance value of
R24/R13/R14. Since the feed current flowing through R24 will generate a voltage drop,
this solution is not suitable for antennas with high power consumption.

UC-08-M32 EN R1.0 Antenna Circuit 11
Dual buffer/driver
with open-drain outputs
0805
U4 LT6000IDCB#TRMPBFQ1
Si2333CDS-T1-GE3
U6 SN74LVC2G07DBVR U2 SN74LVC2G07DBVR
Dual buffer/driver
with open-drain outputs
Figure 4-1 Antenna Detection Circuit
Table 4-1 Truth Table of the Antenna Detection Circuit
ANT-OFF
ANT-DETECT
ANT-SHORT-N
1
X
X
The antenna feed supply is
turned off
0
0
0
An error occurred in the circuit
0
0
1
The antenna feed current < 50
mA; no antenna detected
0
1
0
The antenna feed circuit is
shorted to ground
0
1
1
The antenna feed current > 50
mA; the antenna status is
normal
Figure 4-2 Antenna Detection Circuit on the Bottom of UM980eb

UM980eb User Manual
12 Antenna Circuit UC-08-M32 EN R1.0
4.2 Antenna Feed Circuit
The antenna feed circuit consists of the anti-reverse current design, anti-surge design,
filter inductors, and ESD protection.
The supply voltage can be selected from 5 V, VCC_RF or ANT_BIAS3 through
R31/R29/R30. When using the 5 V voltage or VCC_RF, the antenna detection circuit on
UM980eb will be bypassed.
The ESD protection diode should support high-frequency signal (above 2000 MHz).
Nexperia PESD5V0F1BL is recommended here.
J5
Figure 4-3 Antenna Feed Circuit
Figure 4-4 Antenna Feed Circuit on the Bottom of UM980eb

UC-08-M32 EN R1.0 LED Indicators 13
5LED Indicators
There are LED indicators on UM980eb to indicate the working status of each functional
unit.
Figure 5-1 LED Indicators
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
functions, as shown in the figure below.

UM980eb User Manual
14 UM980 Peripheral Design UC-08-M32 EN R1.0
Figure 5-2 Markings on the Right of the LED Indicators
6UM980 Peripheral Design
TVS anti-surge protection is added at the input of the UM980 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.
VCCIN powers the UM980 module only. R33 is a large-size resistor (with high rated
power) to ensure the current capability. In the figure below, a 0805 resistor is used.
Removing R33, 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 UM980.

UC-08-M32 EN R1.0 UM980 Peripheral Design 15
0805
U1A UM980
Figure 6-1 UM980 Peripheral Design
Silkscreen markings are printed around the UM980 module to identify the resistors,
which is convenient for measurement.
Figure 6-2 UM980 Peripheral Circuit
The GND pads at the bottom of the module should be grounded to ensure heat
dissipation. The UM980eb has copper exposed on the bottom of the UM980 module,
which not only enhances heat dissipation, but also provides a large area for grounding
and is convenient to test.