NEO-8Q / NEO-M8 - Hardware integration manual 
UBX-15029985 - Production information  Design  Page 11 of 12 
C1-Public     
 
2  Design 
2.1  Pin description 
Function  Pin  No.  I/O  Description  Remarks 
Power  VCC  23    Supply voltage  Provide clean and stable supply. 
GND 
10, 
13, 24
  Ground 
Assure a good GND connection to all GND pins of the module, 
preferably with a large ground plane. 
V_BCKP  22   
Backup supply 
voltage 
It is recommended to connect a backup supply voltage to 
V_BCKP in order to enable warm and hot start features on the 
positioning modules. Otherwise, connect to VCC. 
VDD_USB  7   
USB power 
supply 
To use the USB interface, connect this pin to 3.0 – 3.6 V.  
If no USB serial port used connect to GND. 
Antenna  RF_IN  11  I 
GNSS signal 
input from 
antenna 
The connection to the antenna must be routed on the PCB. 
Use a controlled impedance of 50 Ω to connect RF_IN to the 
antenna or the antenna connector. 
VCC_RF  9  O 
Output voltage 
RF section 
VCC_RF can be used to power an external active antenna. 
UART 
TXD / SPI MISO
   
20  O 
UART_TX/ SPI 
MISO 
Communication interface, 
can be programmed as TX_READY for DDC interface. 
If pin 2 low => SPI MISO. 
RXD / SPI MOSI  21  I 
UART_RX / SPI 
MOSI 
Serial input. Internal pull-up resistor to VCC. Leave open if not 
used. If pin 2 low => SPI MOSI. 
USB  USB_DM  5  I/O  USB I/O line  USB bidirectional communication pin. Leave open if unused. 
USB_DP  6  I/O  USB I/O line 
System  TIMEPULSE 
TIMEPULSE1 
(NEO-M8T) 
3  O 
Timepulse 
signal 
Configurable Timepulse signal (one pulse per second by 
default). Leave open if not used.  
SAFEBOOT_N  
TP2 / 
SAFEBOOT_N 
(NEO-M8T) 
1  I  SAFEBOOT_N  SAFEBOOT_N, leave OPEN 
I/O 
TP2 / 
SAFEBOOT_N 
Configurable Timepulse2 signal 
SAFEBOOT_N, leave open if not used. Do not pull low during 
reset. 
EXTINT  4  I 
External 
interrupt 
External interrupt pin. 
Internal pull-up resistor to VCC. Leave open if not used. 
Function is disabled by default. 
EXTINT0 
(NEO-M8T) 
RESERVED 
EXTINT1 
(NEO-M8T) 
15  -  Reserved  Leave open. 
I 
External 
interrupt 
External interrupt pin. 
Internal pull-up resistor to VCC. Leave open if not used. 
Function is disabled by default. 
SDA / SPI CS_N  18  I/O  DDC data / SPI 
CS_N 
DDC data.  
If pin 2 low => SPI chip select. 
SCL / SPI CLK  19  I  DDC Clock / SPI 
SCK 
DDC Clock.  
If pin 2 low => SPI clock. 
LNA_EN  14  O  LNA_EN 
Antenna control can be used to turn on and off an optional 
external LNA. 
RESERVED 
(NEO-M8M) 
 
-  Reserved  Leave open. 
RESET_N  8  I  Reset input  Reset input 
D_SEL  2  I  Selects the 
interface 
Allow selecting UART/DDC or SPI 
open-> UART/DDC; low->SPI 
RESERVED  16, 17
-  Reserved  Leave open. 
Table 2: NEO-8Q and NEO-M8 series pinout