The A21B is an NXP (formerly Freescale) QorIQ based single-board computer for embedded industrial applications. The SBC features full VME64 support and can be used as a master or a slave in a VMEbus environment. The A21B provides 1 MB local dual-ported SRAM for slave access and communication between the local CPU and another VMEbus master.

The CPU card comes with a single-core P1013 or dual-core P1022 QorIQ processor with up to 1.067 GHz clock frequency and a serial communication architecture. With two Gigabit Ethernet ports and one RS232 COM at the front, and DDR3 SDRAM with ECC, Flash and FRAM, the board offers the crucial basics of an industrial computer. To satisfy your needs for mass storage, you can use microSD cards and mSATA plug-in modules.

In addition, the A21B can be equipped with up to three M-Module mezzanine cards supporting both front I/O and rear I/O. M-Modules are ideal for real-world I/O like analog/binary process and instrumentation input/output. The modular combination of I/O functionality on a single-board computer allows to build up tailored control systems which appear as customized solutions based on standard components.

Its sister card, the A21C, offers two PMC/XMC slots instead of M-Modules, for different I/O requirements.

Where there's a need for even more or other I/O, the A21B also includes a custom I/O mezzanine card option that reduces the board by one M-Module but provides interfaces like USB 2.0, COM or even custom I/O controlled by the onboard FPGA. The mezzanine card is always an entirely customized adapter PCB, including front I/O, and makes the A21B a semi-custom solution.

The A21B supports operation in a -40 °C to +85 °C temperature range, and the board withstands shock and vibration.

The CPU board is supported by the U-Boot Universal Boot Loader, which can be used for bootstrapping operating systems, for hardware testing, or for debugging applications without running any operating system.