Parity or computation errors can lead to interesting situations in motor control or similar high-accuracy tasks. With the TMPM4K family, Toshiba combines an ARM Cortex-M4 core with various security-related and analog-interfacing peripherals.

Thanks to its ARM Cortex-M4 core, these microcontrollers are supported by various ecosystem players. This means that most code can be recycled easily, and work seen when adapting code to classic high-security microcontroller cores can be avoided completely.

RAMP for Advanced Memory Protection

Even though memory errors are comparatively rare, their occurrence can lead to significant damage. In the case of the TMPM4K, Toshiba augments the memory controller with a parity function, which the datasheet describes as follows:

The RAM parity (RAMP) generates an even parity for one byte data at the timing of writing data to RAM and stores it to RAM at same time. The RAMP checks that the total number of 1s in the data and parity bit is even when the CPU read data in RAM. When parity errors is detected, the RAM parity interrupt occurs. The error status and address which the error generated in can be monitored. A parity error can be detected in real time, since parity generating/checking is performed by the hardware

Most memory errors can be detected automatically, permitting the software to either re-compute or shut the system down to prevent erroneous control outputs. The system also comes with features intended to protect the code on the device---in particular, various gating options disable memory readback and other problematic interfacing possibilities.

Various devices for optimal performance

Toshiba provides various housings for the TMPM4K device. Two of them are shown in the figures below. The TMPM4KNFYADFG comes in a QFP100 housing, while the TMPM4KMFYAFG is an LQFP80.

Given that Toshiba intends to use these controllers on motors, analog peripherals are provided. Firstly, the device has a 12-bit analog-to-digital converter, meaning analog data can be acquired without adding an external device to the circuit. Furthermore, an integrated OpAmp provides pre-amplification, thereby reducing the amount of external components required for signal conditioning.

Finally, a combination of two peripheral devices enables closed-loop control of motors. Particularly, the Advanced programmable motor control circuit, or A-PMD for short, is responsible for generating the control signals, while the Advanced Encoder input circuit can monitor an encoder to provide an accurate image of the motor position without additional hardware or software. The part is intended for controlling brushless DC motors; the hardware units can be used to generate the control waveforms required to keep the motor-driver integrated circuit happy. As for the Advanced Encoder Input Circuit, the circuit combines advanced noise canceling with an incremental encoder analysis system. Finally, the peripheral device can be adjusted to work with hall sensors.

In addition, the Toshiba TMPM4K microcontroller provides designers with a variety of digital interfaces, such as I2C and SPI, which means that digital sensors can be integrated into the solution at hand.

Conclusion

If a task requires motor control, high-level security, and the computing power of an ARM core, Toshiba's TMPM4K microcontroller family is an excellent choice. The array of high-quality integrated peripherals keeps the resulting PCB design compact.