From the conventional host CPU control IF, the following IF is supported as an IF for connection with peripheral peripherals using the WP series as the main CPU.

- Link: USB2.0, UART, HSIC, SPI, I2C, SDIO
- Digital: GPIOs
- Audio: I2S, PCM
- Analog: ADC

The built-in CPU specifications are as follows, and if it is a general-purpose CPU, it has a capacity that can sufficiently secure resources.

- Cortex A7 32bit RISC

- Processing speed: 1.3GHz

- Flash: 220MB (Total: 512MB)

- RAM: 128MB (Total: 256MB)

The WP series can be processed using an application framework called "legato" that runs on Semtech's proprietary Linux Base Distribution.
Because legato is open source, it is possible to not only develop your own applications, but also to use the source code via the legato Forum.
As for the development environment, development can be easily performed using command line-based development like Legacy Linux OS, or using Developer Studio, an integrated development environment that supports Linux and Legato Framework.

*Click the image to move to the legato forum (external link)

WP series Firmware is largely divided into four partitions.

[Modem Firmware]

- Perform wireless communication control (RF control) using cellular networks with carrier base stations.

- This partition performs all RF control, such as authentication with carrier base stations using SIM cards, receiving packets from carrier base stations and processing conditional branches, and measuring electric field strength.

- Based on Qualcomm's Chipset Firmware, basic RF control has been implemented in Basic, so from the outside, only the application part such as connection/disconnection commands and error handling needs to be designed.

- Customization by the customer is not possible, and after carrier IOT authorization is obtained, firmware will be released irregularly by Sierra.

[Yocto Firmware]

- Refers to the Native Linux Operation System part (Kernel).

- Control equivalent to native Linux is possible, including bootloader control, built-in device control, and command line control.

- It can be controlled using the Yocto Framework packaged by Semtech, and it is also possible to install it from scratch by selecting functions like Embedded Linux.

[Legato Firmware]

- Legato Application Framework that runs on Yocto Framework.

- It is possible to control the Modem Firmware to a certain extent using custom commands, such as setting SIM information and monitoring the radio environment.

- When using a Native Linux-based general-purpose Application, it is managed by this Partition. (e.g. pppconfig)

[Legato Application]

- This is the Custom legato Application section created by the customer.

- It is managed by file system and can be designed by C language-based programming language.

In the WP series, the hardware specifications are determined under a concept called CF3.
Based on the concept of "Common Form Factor," it supports HW pin compatibility to minimize module changes that accompany changes in communication standards/destination, and changes in baseboard HW design that accompany module changes.

With CF3, there is also a WP-specific socket connector, so you can simply replace the module according to your destination.