This core, whose evolution from the M0 introduces optimizations in energy efficiency, interrupt latencies and advanced debugging, is closely integrated with the Nested Vectored Interrupt Controller (NVIC) and the SysTick timer, facilitating fast and deterministic responses to critical events, such as smoke threshold crossing or external alerts.
The HT32L62141 operates at speeds up to 48 MHz, designed to maximize performance with low power consumption. It features 64 KB of Flash memory and 8 KB of SRAM. Additionally, it incorporates a Flash accelerator to improve execution efficiency and multiple power-saving modes that allow adjustment of the balance between wake-up latency and standby power consumption, while also meeting the 10-year battery life requirement for smoke detectors. The inclusion of a six-channel Peripheral Direct Memory Access (PDMA) offloads repetitive data transfer tasks from the core, such as continuous A/D reads or data shifting between peripherals and memory.
One of the most notable innovations of the new HT32L62141 is the integration of an analog front end (AFE) for smoke detection and a buzzer controller with a 9V boost converter.
The smoke detection AFE offers two programmable constant current channels to excite the smoke sensor and communicates with the digital section via a one-wire protocol, facilitating measurement readings and sensitivity parameter adjustments. The AFE also includes two operational amplifiers capable of processing signals without the need for additional external components. This is complemented by a high-precision voltage reference and a 12-bit A/D converter capable of sampling multiple channels at up to 1 Msps: a combination that ensures stable and fast measurements.
The buzzer controller supports both passive 2-pin and active 3-pin buzzers. Thanks to the internal converter, it generates the necessary voltage to activate the buzzer even with a limited supply voltage. Furthermore, it integrates a Buzzer Watchdog Timer (BWDT): if the microcontroller fails to periodically renew the supervisory signal, it triggers an audible alarm to detect faults and enhance system reliability.
Beyond its specific functionality for smoke detectors, the HT32L62141 also integrates a hardware divider, a CRC16/32 for fault detection, multiple timer modules, an RTC, and multiple communication interfaces (I²C, SPI, USART/UART).
The microcontroller is offered in a 64-pin (7 x 7 mm) LQFP package and is compatible with several well-known development environments—Keil, IAR, SEGGER, and GNU GCC—as well as Holtek's proprietary HT32-IDE, which is offered free of charge. In addition, Holtek provides firmware libraries and application notes that accelerate commissioning, reduce the learning curve, and shorten development time.
