MC9S08LG32CLK

The MC9S08LG32CLK from NXP (formerly Freescale) is a member of the HCS08 family of 8-bit microcontrollers specifically designed for LCD-based embedded applications. The device integrates a 4-backplane x 40-segment LCD controller/driver capable of directly driving up to 160 LCD segments without external driver ICs, making it ideal for consumer appliances, thermostats, meters, and other products with segment-type LCD displays. The HCS08 core achieves up to 20MHz bus frequency with a single-cycle instruction execution architecture for efficient code performance. The 32KB Flash and 2KB SRAM provide sufficient memory for application code, LCD display data, and runtime variables. The 12-bit ADC with 16 channels supports high-resolution analog measurement for sensor interfaces, while two Timer/PWM modules (TPM1 with 2 channels, TPM2 with 3 channels) provide flexible timing and PWM generation for motor control, buzzer driving, and other timing functions. The dual SCI (UART) ports, SPI, and I2C interfaces enable communication with external peripherals, sensors, and host systems. The LCD controller supports multiple backplane configurations (2, 3, or 4 backplanes) and generates the AC waveforms required for LCD driving with configurable frame frequency. The low-power modes (Stop2, Stop3, Wait) combined with the LCD controller’s ability to maintain display content in Stop3 mode allow the display to remain active while the CPU is sleeping, minimizing power consumption in battery-powered applications.

The MC9S08LG32CLK operates as an 8-bit HCS08 microcontroller with integrated LCD driver. Key subsystems include: (1) HCS08 Core – an enhanced 6800-based 8-bit CPU with a 3-stage pipeline; most instructions execute in a single bus cycle; the CPU supports 16-bit indexed addressing and stack pointer relative addressing; the background debug mode (BDM) provides single-wire in-circuit debugging without using CPU resources; (2) LCD Controller – generates the multiplexed AC waveforms for driving segment-type LCD displays; the controller supports 2, 3, or 4 backplane (common) configurations; the 40 segment outputs are directly driven by internal charge pumps; LCD data is stored in a dedicated RAM buffer; the frame frequency is programmable (typically 30-100Hz); in Stop3 mode, the LCD controller can continue to operate from the internal oscillator while the CPU is halted; (3) Clock System – an internal 31.25kHz RC oscillator provides the default clock source; an internal 32kHz oscillator provides the RTC clock; an external oscillator (32kHz to 20MHz crystal) can be used for higher accuracy; the ICS (Internal Clock Source) module can multiply the internal clock to higher frequencies using an FLL; (4) 12-bit ADC – a successive-approximation ADC with 16 external channels; the ADC can operate in 8-bit or 12-bit mode; automatic compare function can generate interrupts when conversion results exceed a threshold; (5) TPM Modules – two Timer/PWM modules with edge-aligned or center-aligned PWM, input capture, and output compare capabilities.

• Thermostat: LCD displays temperature setpoint and current reading, 12-bit ADC reads NTC thermistor, TPM drives relay
• Metering: 4×40 LCD shows multi-tariff energy readings, 12-bit ADC reads current/voltage sensors, SCI for data download
• Appliance display: 160-segment LCD for microwave/oven control panel, capacitive buttons via ADC, dual SCI for communication
• Portable instrument: battery-powered LCD meter with Stop3 mode maintaining display, 2KB RAM for measurement buffer