STMicroelectronics SCT-TPM-RASPIHE4

Overview

SCT-TPM-RASPIHE4 from STMicroelectronics is an official Raspberry Pi® extension board integrating the ST33TPHF2XSPI Trusted Platform Module (TPM 2.0, firmware v1.769) in VFQFPN32 package. It provides SPI-based TPM connectivity via Raspberry Pi's GPIO header (CE0, MOSI, MISO, SCLK, RST, PIRQ, PP), supports Linux kernel ≥4.8 with tpm_tis_spi driver, and enables secure boot and cryptographic key storage for embedded Linux development.

For engineers reviewing the SCT-TPM-RASPIHE4 datasheet, SCT-TPM-RASPIHE4 pinout, SCT-TPM-RASPIHE4 application, or SCT-TPM-RASPIHE4 equivalent, this board serves as a production-ready evaluation platform for TCG-compliant TPM 2.0 integration on Raspberry Pi 3/4/5, requiring verified device tree overlays, kernel config flags (CONFIG_TCG_TIS_SPI=m), and SPI clock frequency ≤25 MHz.

Technical Context

The SCT-TPM-RASPIHE4 implements a hardware-rooted trust anchor by bridging the ST33TPHF2XSPI TPM - a TCG 2.0-compliant, Arm®-based secure microcontroller - to Raspberry Pi's SPI bus using dedicated GPIO pins (CE0, MOSI, MISO, SCLK) and control signals (RST, PIRQ, PP). It routes all required power (3.3 V), ground, and timing signals without level-shifting.

It includes a 40-pin female header for direct Raspberry Pi stacking, a 40-pin male header for signal probing or daisy-chaining extension boards, and an optional P1 test point (across 10 Ω resistor R4) enabling real-time TPM current measurement during cryptographic operations.

Key Specifications

Availability

SCT-TPM-RASPIHE4 is available at Aetrix Electronics and suitable for secure boot validation, embedded Linux attestation, IoT device identity provisioning, and cryptographic key management requiring stable component supply and traceable sourcing.

Supply support for SCT-TPM-RASPIHE4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, analog ICs, MEMS, and secure elements for industrial, automotive, and consumer applications.

The STPM4RasPI product line delivers certified, ready-to-deploy hardware interfaces for ST's ST33 TPM family - engineered specifically to accelerate TCG 2.0 adoption on ARM-based SBCs like Raspberry Pi without custom PCB design.

FAQ

Does SCT-TPM-RASPIHE4 support I²C interface?

No. This variant is SPI-only and ships with the ST33TPHF2XSPI TPM. I²C functionality is provided only on other SKUs such as SCT-TPM-RASPIHD5 and SCT-TPM-RASPIHE1, which integrate ST33TPHF2XI2C. The board's hardware routing and device tree overlay are specific to SPI signaling and cannot be reconfigured for I²C.

What Linux kernel configuration is mandatory for TPM driver recognition?

Kernel ≥4.8 is required, with CONFIG_TCG_TPM=y, CONFIG_TCG_TIS_CORE=y, and CONFIG_TCG_TIS_SPI=m (or =y). The device tree overlay must declare "st,st33htpm-spi" compatibility and assign reg=<0> to CE0. Without these, /dev/tpm0 will not appear after boot.

Can SCT-TPM-RASPIHE4 be used with Raspberry Pi 1 or Zero?

No. It requires a 40-pin GPIO header and full SPI peripheral support. Only Raspberry Pi models with 40-pin headers (Pi 2B v1.2+, Pi 3A+/B/B+, Pi 4B/400, Pi 5) are supported. Pi 1 Model B+ and Pi Zero lack both the pin count and kernel-level SPI TPM driver maturity for this board.

Is the ST33TPHF2XSPI TPM soldered or socketed on SCT-TPM-RASPIHE4?

The ST33TPHF2XSPI TPM is permanently soldered onto the board per ST's official STPM4RasPI design. It is not socketed or field-replaceable. Replacement requires board-level rework or ordering a new unit - consistent with ST's production release configuration for this SKU.