NUVOTON MS51XB9AE

The MS51 is an enhanced 8-bit 8051-core MCU with Flash (1T operating mode), fully compatible with the standard 80C51 instruction set while delivering higher performance. The MS51FB9AE / MS51XB9AE / MS51XB9BE embeds an 18K Flash memory region, commonly referred to as APROM, for storing user program code. This Flash memory region supports In-Application Programming (IAP), allowing program code to be updated via on-chip firmware. IAP also provides user-configurable program regions or data storage areas. The data storage area can be read and written via IAP, and data reads can also be performed using the MOVC instruction. The MS51 features an additional memory region called LDROM, which typically stores the boot code for In-System Programming (ISP). The LDROM size is configurable up to 4K bytes. For convenient programming and verification, the entire Flash region supports parallel programming and ICP programming. Flash encryption via configuration bits prevents program code from being read out. The MS51FB9AE / MS51XB9AE / MS51XB9BE offers a rich set of special function modules, including: 256 bytes SRAM, 1K bytes XRAM. Up to 18 standard I/O pins. Two standard 16-bit timer/counters: Timer 0 and Timer 1; one 16-bit timer with 3-channel input capture mode: Timer 2; one Watchdog Timer (WDT); one self-wake-up timer (WKT); one timer with auto-reload capability for standard baud rate generation: Timer 3. Two standard UARTs with frame error detection and automatic address recognition. One SPI, one I²C, 6-channel enhanced PWM output, and 8-channel 12-bit ADC. These features generate up to 18 interrupt sources with 4-level interrupt priority configuration. The MS51FB9AE / MS51XB9AE / MS51XB9BE supports 3 clock source inputs, all of which support on-the-fly software switching that takes effect immediately. The 3 clock sources include: external clock, 10kHz internal RC oscillator clock, and a 16MHz internal high-speed clock factory-calibrated to ±1% accuracy at room temperature. The MS51 provides additional power monitoring and management modules, such as power-on reset and 4-level low voltage detection, ensuring stable system operation during power-up and power-down. The MS51 can operate in two low-power modes — Idle mode and Power-down mode — selectable by software. In Idle mode, the main clock is disabled while certain functional modules remain active. In Power-down mode, all clocks are shut down to minimize power consumption. In normal operating mode, the main clock can optionally be divided down, providing flexible trade-offs between power consumption and performance. With high performance, rich functional modules, and versatile configurations, the MS51 is well-suited for a wide range of applications, from home appliances to demanding control systems such as motor control.