Overview
This page describes how to connect and configure the Broadcom GPS Evaluation Kit (EK).
Description of Thames EK
The Thames EK has two separate BCM4751 chips. One dedicated for the INT_LNA SMA input, another dedicated for the EXT_LNA SMA input. Be sure to use the slider switch to select corresponding chip per the input signal. Note that newer EKs such as Roadrunner (BCM2076) and Beluga (BCM47511) are similar to Thames, unless noted otherwise.
Thames Frontal View - components left to right: USB port, T/R/Power LED, RS232 Serial Port
Thames with lid removed at bottom
Thames Disassembled Bottom View
Thames Disassembled, note the internal patch antenna is just below the label
Thames SMA Connectors: configured to use internal antenna with external LNA shown
- ANTENNA RF is output from internal patch antenna
- EXT LNA RF is input to one BCM4751 chip
- INT LNA RF is input to another BCM4751 chip
Thames slider switches: configured to utilize chip for EXT LNA input
Thames with external RF configured for INT LNA
Configure GPS Signal Inputs on EK
- On Thames (BCM4751)
- It can be configured to use the internal antenna or external RF source
- It can be configured to utilize the chip for EXT LNA or INT_LNA
- Examples:
- To use the internal antenna, use the U-connector to connect the ANTENNA SMA connector to SMA of
- INT_LNA => ensure slider switch to INT_LNA
- EXT_LNA => ensure slider switch to EXT_LNA
- To use external RF source, such as simulator, connect the RF connector to SMA of
- INT_LNA => ensure slider switch to INT_LNA
- EXT_LNA => ensure slider switch to EXT_LNA
- On BASS (BCM4750)
BASS slider switch
- To use the internal antenna, ensure the slider switch is on "INTERNAL ANTENNA".
- To use external antenna, such RF feed from GPS simulator, ensure the slider switch is on "EXTERNAL INPUT".
- Expose the GPS EK to valid GPS signals, either to open-sky or simulator output when you run the SDK.
Connect The EK For Serial Interface
- Connect the GPS EK (BASS, Thames, or Piranha) to a computer (running Linux or Windows) with a USB cable. Ensure the power LED is on.
- On Linux, the USB driver is built-in, no additional installation required. However, a patch must be applied to use the GPIO. See Running SDK on Linux (Ubuntun as example here) for details.
- Observe the presence of /dev/ttyUSB0 when EK is connected to USB cable.
- Observe the absence of /dev/ttyUSB0 when EK is disconnected from computer.
- Optional: you may also connect to EK using RS232 cable to the PC's serial port. However, you still need to connect USB cable to power the EK. You will NOT have GPIO control to the GPS chipset.
Connect The EK For I2C Interface with TotalPhase Aardvark
- Do not connect the TotalPhase Aardvark to PC until the driver http://www.totalphase.com/support/product/aardvark_i2cspi/ is installed.
- Obtain the BASS Test Fixture (TF) and 5V power supply from Broadcom GPS hardware engineer.
- On TF, jumper J5 to "BASS"
- On TF, jumper J6 to "I2C"
- On TF, jumper J7 to "ON"
BASS Test Fixture
- Connect the 10-pin Aardvark connector to J4 of TF. Be sure the align pin-1 as marked by the arrows on J4 and Aardvark connector.
BASS Test Fixture Connected to Aardvark
- Remove the two screws at the bottom of EK to disassemble black plastic case and expose the EK's circuit board. Use Electrostatic Discharge cautions.
- Connect the TF to the EK's 24-pin connector J8.
BASS Test Fixture Connected to Thames
- Connect 5V power supply to J1 of TF and ensure the EK's power LED is on.
- Install Aardvark driver on PC and upgrade the Aardvark firmware to latest http://www.totalphase.com/support/product/aardvark_i2cspi/.
- Connect PC to Aardvark with a USB cable.
The next step Update GPS Configuration File gpsconfig.xml is to configure to run the SDK.