Physical specifications of the RasPiGNSS “Aldebaran” module

  • Dimensions: 41 x 56mm (excluding SMA connector)
  • Weight: 22g
  • Antenna connector: SMA female
  • Power supply: through Raspberry Pi expansion port (P1)
  • Serial communications: through Raspberry Pi expansion port (P1)
  • For detailed electrical and environmental specifications see the NV08C-CSM datasheet.

RasPiGNSS expansion port (P1) connections

P1 PinGPIOSymbolDescription
P1-1 +3.3VPower supply to NV08C digital I/O
P1-2 +5VAnalog and digital power supply
P1-4 +5VAnalog and digital power supply
P1-6 GNDGround
P1-7GPIO4SW1Tactile switch 1
P1-8GPIO14RX1Serial receive of NV08C, RasPi TXD0
P1-10GPIO15TX1Serial transmit of NV08C, RasPi RXD0
P1-11GPIO17SW2Tactile switch 2
P1-12GPIO18RSTReset of NV08C
P1-13GPIO271pps1pps signal (GPIO1) of NV08C
P1-15GPIO22LED1Red indicator LED
P1-16GPIO23LED2Yellow indicator LED
P1-18GPIO24LED3Green indicator LED

Note: LEDs or switches are not controlled by the NV08C, all I/Os are fully programmable from the RasPi.
All LEDs are standard 20mA types and are driven from the RasPi via a MOSFET.
Configure pins 15, 16, and 18 as outputs and set them high to switch them on.
All switches are directly wired to ground. Enable pullups on pins 7, and 11, and do debouncing in software to read them correctly.

LCD connector

The LCD connector can be used to connect a HD44780-compatible character LCD display to the Raspberry Pi. Its pins are directly connected to Raspberry Pi GPIOs, so you can use them just as standard GPIOs as well. The connector exhibits the standard 14-pin connections, excluding backlight LED anode/cathode connections (which may be connected to +5V and GND pins of other connectors).

Note that the display is driven in 4-bit (nibble) mode in order to save on GPIOs, so you need to do two nibble transfers to send one byte to the character LCD. Note also that functionality is limited to writing the LCD only, as the HD44780 LCD controller works with +5V I/O levels that would damage the Raspberry Pi’s GPIOs when driven for reading. Writing however is no problem as the +3.3V high level of the Raspberry Pi GPIOs fits well to the expected TTL high level of the HD44780. Therefore LCD5 RW is always connected to ground, allowing only write operations to the LCD.

LCD pinP1 pinGPIOSymbolDescription
LCD2P1-2, P1-4Vcc+5V power supply
LCD3VELCD contrast adjustment
LCD4P1-22GPIO25RSRegister Select (0: command, 1: data)
LCD5P1-6RWRead/¬Write (connected to GND)
LCD6P1-26GPIO7ENEnable (clock, also SPI0_CE1_N)
LCD7P1-6D0GND (4bit mode)
LCD8P1-6D1GND (4bit mode)
LCD9P1-6D2GND (4bit mode)
LCD10P1-6D3GND (4bit mode)
LCD11P1-24GPIO8D4D0 (shared with SPI0_CE0_N)
LCD12P1-21GPIO9D5D1 (shared with SPI0_MISO)
LCD13P1-19GPIO10D6D2 (shared with SPI0_MOSI)
LCD14P1-23GPIO11D7D3 (shared with SPI0_SCLK)

Note that you cannot use the LCD and SPI ports at the same time, as all SPI lines are also used by the LCD. When using SPI only, you may however use the remaining GPIOs from the LCD connector (GPIO7 and GPIO25) for other purposes.

SPI connector

The SPI connector allows connecting any supported SPI device to the Raspberry Pi’s SPI0 bus. It uses a standard 2×3 (6-pin) connector with a fairly standard pinout.

Note that while the power supply is +5V, all I/O signals are +3.3V level! Observe compatibility of the SPI device pinout and logic levels, otherwise you may damage your Raspberry Pi!

SPI pinP1 pinGPIOSymbolDescription
SPI1P1-21GPIO9SPI0_MISOSPI Master-In Slave-Out
SPI2P1-2, P1-4Vcc+5V power supply
SPI4P1-19GPIO10SPI0_MOSISPI Master-Out Slave-In
SPI5P1-24GPIO8SPI0_CE0_NSPI select signal (negated, active low)

Note that you cannot use the LCD and SPI ports at the same time, as they share many signals.

I2C connector

The I2C connector provides access to the Raspberry Pi’s I2C1 bus.

I2C pinP1 pinGPIOSymbolDescription
I2C1P1-5GPIO3SCL1I2C clock
I2C2P1-3GPIO2SDA1I2C data
I2C4P1-1+3V3+3.3V power supply
I2C5P1-2, P1-4+5V+5V power supply

Note that all I2C signals (SCL1, SDA1) have +3.3V logic levels. Connecting to a device with +5V logic levels may damage your Raspberry Pi! The I2C5 +5V pin is provided for convenience only, e.g. for devices providing an internal voltage regulator (as some Pololu IMUs do). There are two on-board 4k7 pull-up resistors for SDA and SCL of the I2C bus, which can be activated by shortening two solder bridges located between the big goldcap and the right push button on the top side of the Aldebaran board.

NV08C 2nd serial port connector

The SER connector provides access to the second serial port of the NVS NV08C-CSM GNSS chip on the RasPiGNSS “Aldebaran”.

SER pinSymbolDescription
SER1TX2NV08C port 2 serial transmit
SER2RX2NV08C port 2 serial receive
SER4+3V3+3.3V power supply
SER5+5V+5V power supply

Note that all SER signals have +3.3V logic levels. Connecting to a device with +5V logic levels may damage the NV08C-CSM chip of the RasPiGNSS! The SER5 +5V pin is provided for convenience only, e.g. for devices providing an internal voltage regulator.

⯅ RasPiGNSS "Aldebaran" Installation ⯈