The distributor Waveshare recently featured the Raspberry Pi Compute Module 4S (CM4S), a System on Module based on the Raspberry Pi 4 Model B, intended for industrial applications. It retains the form factor of the older Compute Module 3 and 3+, offering multiple standard peripherals.

The CM4S is equipped with a Broadcom BCM2711 quad-core 64-bit Cortex-A72 processor running at 1.5GHz. It offers various memory configurations, including 1GB, 2GB, 4GB, or 8GB of LPDDR4-3200 SDRAM with ECC, and optional eMMC flash storage of 8GB, 16GB, or 32GB.

There is also a Lite version, CM4SLite, according to the product brief, which comes without eMMC for cost-sensitive applications.

The CM4S maintains the form factor of the older Compute Module 3 and 3+, complying with the JEDEC MO-224 mechanical specification for 200-pin DDR2, though it is not electrically compatible with DDR2-SODIMM modules.

This module supports extensive connectivity options with 46x GPIO signals, one USB 2.0 port, and multiple video outputs, including HDMI 2.0 and MIPI DSI and CSI interfaces. It also provides advanced multimedia support with H.265 (HEVC) and H.264 decoding and encoding, along with OpenGL ES 3.0 graphics.

Power requirements for the CM4S include VBAT (2.5V to 5V) and +3.3V supplies. The +1.8V supply used in older modules is no longer necessary but can be provided for backward compatibility. The CM4S is designed for long-term availability, with production expected to continue until at least January 2034.

Waveshare indicates that this SoM is compatible with their Compute Module I/O Board with PoE, Compute Module Industrial IoT Base Board, and Compute Module I/O Board Plus.

Specifications listed for the Raspberry Pi Compute Module 4S include:

• Memory/Storage:
  • Up to 8GB RAM
  • Up to 32GB eMMC
• Display:
  • 1× HDMI 2.0 port (up to 4Kp60 supported)
  • 1× 2-lane MIPI DSI display interface
  • 1× 4-lane MIPI DSI display interface
  • 1× composite TV out (PAL or NTSC)
• Camera:
  • 1× 2-lane MIPI CSI camera interface
    1× 4-lane MIPI CSI camera interface
• I/O Interfaces:
  • 46× GPIO (1.8V or 3.3V)
  • 6× UART, 6× I2C, 6× SPI
  • 1× SDIO 2.0 (CM4SLite)
  • 1× PCM
  • 2× PWM channels, 3× GPCLK outputs
• USB:
  • 1× USB 2.0 port (high speed)
• Power:
  • 2.5~5V / 3.3V DC
• Operating Temperature:
  • -20℃ to 80℃
• Mechanical:
  • 67.6  × 31.0mm

Further information

Currently, the only Raspberry Pi Compute Module 4S variant available on Waveshare is the one with 8GB RAM and 32GB eMMC for $109.99, which differs from the suggested price of $75.00 as mentioned in the product brief.