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
|P1-1||+3.3V||Power supply to NV08C digital I/O|
|P1-2||+5V||Analog and digital power supply|
|P1-4||+5V||Analog and digital power supply|
|P1-7||GPIO4||SW1||Tactile switch 1|
|P1-8||GPIO14||RX1||Serial receive of NV08C, RasPi TXD0|
|P1-10||GPIO15||TX1||Serial transmit of NV08C, RasPi RXD0|
|P1-11||GPIO17||SW2||Tactile switch 2|
|P1-12||GPIO18||RST||Reset of NV08C|
|P1-13||GPIO27||1pps||1pps signal (GPIO1) of NV08C|
|P1-15||GPIO22||LED1||Red indicator LED|
|P1-16||GPIO23||LED2||Yellow indicator LED|
|P1-18||GPIO24||LED3||Green indicator LED|
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 pin||P1 pin||GPIO||Symbol||Description|
|LCD2||P1-2, P1-4||–||Vcc||+5V power supply|
|LCD3||–||–||VE||LCD contrast adjustment|
|LCD4||P1-22||GPIO25||RS||Register Select (0: command, 1: data)|
|LCD5||P1-6||–||RW||Read/¬Write (connected to GND)|
|LCD6||P1-26||GPIO7||EN||Enable (clock, also SPI0_CE1_N)|
|LCD7||P1-6||–||D0||GND (4bit mode)|
|LCD8||P1-6||–||D1||GND (4bit mode)|
|LCD9||P1-6||–||D2||GND (4bit mode)|
|LCD10||P1-6||–||D3||GND (4bit mode)|
|LCD11||P1-24||GPIO8||D4||D0 (shared with SPI0_CE0_N)|
|LCD12||P1-21||GPIO9||D5||D1 (shared with SPI0_MISO)|
|LCD13||P1-19||GPIO10||D6||D2 (shared with SPI0_MOSI)|
|LCD14||P1-23||GPIO11||D7||D3 (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.
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 pin||P1 pin||GPIO||Symbol||Description|
|SPI1||P1-21||GPIO9||SPI0_MISO||SPI Master-In Slave-Out|
|SPI2||P1-2, P1-4||–||Vcc||+5V power supply|
|SPI4||P1-19||GPIO10||SPI0_MOSI||SPI Master-Out Slave-In|
|SPI5||P1-24||GPIO8||SPI0_CE0_N||SPI select signal (negated, active low)|
Note that you cannot use the LCD and SPI ports at the same time, as they share many signals.
The I2C connector provides access to the Raspberry Pi’s I2C1 bus.
|I2C pin||P1 pin||GPIO||Symbol||Description|
|I2C4||P1-1||–||+3V3||+3.3V power supply|
|I2C5||P1-2, P1-4||–||+5V||+5V power supply|
Note that all I2C signals (
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”.
|SER1||TX2||NV08C port 2 serial transmit|
|SER2||RX2||NV08C 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"|