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STMicroelectronics has extended its STM8L EnergyLite ultra low-power microcontroller family with new devices offering enhanced features, such as larger program/data memory, high-accuracy time-keeping, a controller for as many as16 touch-sensitive keys, and support for 128-bit AES encryption.
The three variants of the STM8L family are the STM8L151, the STM8L152, and the STM8L162. Each of the new devices has 64 Kbytes of Flash memory, effectively doubling the maximum program/data memory available to developers using the 8-bit STM8L family. SRAM density is also increased to 4 Kbytes. The STM8L152 also adds an enhanced LCD controller that supports larger segments. In a move to enhance security the STM8L162 is also the first device in a new line featuring on-chip 128-bit AES encryption. Common to all the new devices is an enhanced Real-Time Clock (RTC) module offering sub-second accuracy, as well as support for calibration, enabling increased precision in applications requiring time-stamping and accurate synchronisation. These applications include utility metering and use within RF networks. The hardware RTC and its associated automatic wake-up unit have combined current consumption below 1 microamp, allowing developers to use power-saving sleep modes to maximum effect. To meet increased demand for touch sensitive user interfaces in many consumer and professional markets, the new STM8L devices also provide designers with a robust and power-efficient 16-channel touch controller. This provides capacity for 16 individual touch buttons or a combination of up to 10 buttons plus one rotary sensor, equivalent to a dial or knob, and one slider. The entire STM8L family (and ST’s STM32L family using the industry-standard 32-bit ARM Cortex-M3 CPU core) is built using ST’s EnergyLite ultra-low-power platform. This platform combines a proprietary 130nm ultra-low leakage process with ultra low-power non-volatile memory (EEPROM), and achieves dynamic current consumption as low as 150uA/MHz. EnergyLite devices implement a voltage regulator capable of maintaining low operating current at low supply voltages, which provides extra flexibility for designers to minimise the overall energy consumption of their applications. Speed and functionality are not compromised, as the full CPU performance is maintained up to the maximum operating frequency at any supply voltage (Vdd) from 1.65V to 3.6V. In addition, integrated analog peripherals are fully functional at supply voltages down to 1.8V. This can help simplify design as well as helping to minimize overall power demand. The platform also implements multiple power-management modes including a 5.1uA Low-Power Run mode, 3.0uA Low-Power Wait mode, 1.2uA Active Halt with full RTC, and down to 350nA Halt mode. The device can wake from Halt within 4us, enabling frequent use of the lowest-power mode.
