The RPi-Basic Spring adapter allows for easy connectivity between a Raspberry PI and any of the LooUQ Circuit River Stream devices, including our LTEm1 Stream modem. The adapter has a voltage regulator to supply the modem with power derived from the Raspberry PI's 5-volt supply and signal connectivity. For applications where the USB port is utilized (Linux) as the communications path between the R-PI and the modem, the IRQ and SPI-CS traces can be easily cut to prevent unexpected interactions.
The RPi-Basic form-factor matching for the Raspberry PI Foundation HAT specification, but since we have not implemented the GPIO automatic mapping we don't call it a HAT. It is available with either stacking or non-stacking 40-pin I/O header (2nd photo, with LTEm1 attached, shows stacking header).
|Signal Name||Physical Pin||Alias||R-PI|
LooUQ Circuit River Springs are open-hardware and all supporting software/drivers are licensed as open-source. Please visit our GitHub to see our Eagle-CAD design files and our collection of open-source software repositories.
If your application uses the USB interface to the LTEm1 for communications, you will also need to implement 3 GPIO signals to power-on and manage the LTEm1 modem. These are PwrKey, Reset and Status. Status (R-PI input): Indicates that the modem is powered on and ready for command processing. Reset (R-PI output): Forces LTEm1 to initialize. This pin must be setup as R-PI output and set to Low logic level for the LTEm1 to power on. PwrKey (R-PI output): Pulse this pin High (low-high-low) for at least 500 mSec to turn the LTEm1 on, pulse for at least 800 mSec to the the LTEm1 off.