CatsPi Industrial Lite RPi CM4 carrier board features GbE, RS485, Watchdog MCU

We’ve seen a fair deal of Raspberry Pi CM4 carrier boards, and here’s another one courtesy of QwaveSystems with CatsPi Industrial Lite board following Raspberry Pi SBC form factor/dimensions, and equipped with Gigabit Ethernet, RS485, USB ports, as well as a watchdog MCU among other interfaces and features.

Contrary to what the name implies, CatsPi Industrial Lite only works with Raspberry Pi CM4 with eMMC flash, but not the CM4 Lite module since there’s no MicroSD card on the baseboard. It’s not the first Raspberry Pi Compute Module 4 carrier board with RS485, however, as we previously covered CM Hunter also including CAN and 1-wire interfaces, but QwaveSystems’ solution is more compact and mostly mechanically compatible with Raspberry Pi model B SBC’s.

CatsPi Industrial Lite board specifications:

• Compatible SoMs – Raspberry Pi CM4 with eMMC flash only
• Video Output – Micro HDMI port
• Connectivity – Gigabit Ethernet, optional 802.11b/g/n/ac WiFi 5 and Bluetooth 5.0 depending on selected CM4 module
• USB – 2x USB 2.0 host ports, 1x Micro USB port for flashing the firmware using rpiboot
• Serial – RS485 isolated port
• Expansion – 40-pin Raspberry Pi header
• Misc – Switch for Wake or Reset, Microchip ATTiny85 8-bit AVR MCU acting as a watchdog with Linux drivers provided.
• Power Supply
  • 5V/3A via USB Type-C port
  • Power supervisor IC to detect low voltage (drop to 4.63V) and turn off the board
• Dimensions – Around 85.6mm × 56.5mm

What’s harder to find is documentation as either it’s well hidden or simply not available just yet. QwaveSystems has a Github account, but nothing relevant there at this time. I’d assume the board should work in the same way as Waveshare RS485 CAN Hat, and several implementations of a watchdog timer based on ATTiny85 can be found on the Internet. It looks like the company mostly provides support via email or LINE.

The Raspberry Pi CM4 module would be cooled by either a heatsink or a combination with a fan depending on the environmental conditions and typical load for your applications.

CatsPi Industrial Lite is sold on Qwaveshop for 2,300 Baht or $70 plus shipping, but the online checkout process only work when ordering in Thailand, and for shipping to other countries, you’d have to contact them by email, as explained on the shop page.

QwaveSystems is also working on another version, the CatsPi Industrial Pro, that adds a mini PCIe slot for cellular cards (3G/4G/NB-IoT), LoRa or WiFi, as well as a microSIM card slot, an eSIM, RTC, temperature sensor, and a MicroSD card slot for Raspberry Pi CM4 Lite.

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