High-Performance, Power-Efficient and Cost Sensitive Arm® Cortex®-M0+ MCUs


Block Diagram


LPC51U68 MCU Family Block Diagram


Arm Cortex-M0+ Core

  • Running at a frequency of up to 150 MHz
  • Single-cycle multiplier
  • Built-in nested vectored interrupt controller (NVIC)
  • Non-maskable interrupt (NMI) with a selection of sources

On-Chip Memory

  • 256 KB on-chip flash programming memory with flash accelerator and 256 byte page write and erase
  • Up to 96 KB total SRAM composed of up to 64 KB main SRAM, plus an additional 32 KB SRAM

ROM API Support

  • Flash in-application programming (IAP) and in-system programming (ISP)
  • ROM-based USB drivers (HID, CDC, MSC, DFU) and flash updates via USB
  • Booting from valid user code in flash, USART, SPI and I2C
  • Legacy, single and dual image boot

Serial Interfaces

  • Eight flexcomm interface serial peripherals. Each can be selected by software to be a USART, SPI or I2C interface. Two flexcomm interfaces also include an I2S interface, for a total of 2 channel pairs. Each flexcomm interface includes a FIFO that supports USART, SPI and I2S if supported by that flexcomm interface. A variety of clocking options are available to each flexcomm interface and include a shared fractional rate generator
  • I2C supports fast-mode and fast-mode Plus with data rates of up to 1 Mbit/s and with multiple address recognition and monitor mode. Two sets of true open drain I2C pins also support high-speed Mode (up to 3.4 Mbit/s) as a target
  • USB full-speed device interface with option for crystal-less operation

Digital Peripherals

  • DMA controller with 18 channels and 16 programmable triggers, able to access all memories and DMA-capable peripherals
  • Up to 48 general-purpose I/O (GPIO) pins. A majority of GPIOs have configurable pull-up/pull-down resistors, open-drain mode and input inverter
  • GPIO registers are located on AHB for fast access
  • Up to four GPIOs can be selected as pin interrupts (PINT), triggered by rising, falling or both input edges
  • Two GPIO grouped interrupts (GINT) enable an interrupt based on a logical (AND/OR) combination of input states
  • CRC engine

Analog Peripherals

  • 12-bit ADC with 12 input channels and multiple internal and external trigger inputs and sample rates of up to 5.0 MSamples/sec. The ADC supports two independent conversion sequences
  • Integrated temperature sensor connected to the ADC


  • Three standard general purpose timers/counters, four of which support up to 4 capture inputs and 4 compare outputs, PWM mode and external count input. Specific timer events can be selected to generate DMA requests
  • One SCTimer/PWM (SCT) 8 input and 8 output functions (including capture and match). Inputs and outputs can be routed to/from external pins and internally to/from selected peripherals. Internally, the SCT supports 10 captures/matches, 10 events and 10 states
  • 32-bit real-time clock (RTC) with 1s resolution running in the always-on power domain. A high-resolution timer in the RTC can be used for wake-up from all low power modes including deep power-down with 1ms resolution
  • Multiple-channel, multi-rate 24-bit timer (MRT) for repetitive interrupt generation at up to four programmable fixed rates
  • Windowed watchdog timer (WWDT)
  • Ultra-low power micro-tick timer, running from the watchdog oscillator, that can be used to wake up the device from a majority of low power modes

Clock Generation

  • Internal FRO oscillator, factory trimmed for accuracy, that can optionally be used as a system clock as well as other purposes. This oscillator provides a selectable 48 MHz or 96 MHz output, and a 12 MHz output (divided down from the selected higher frequency) that can optionally be used as a system clock as well as other purposes
  • External clock input for up to 25 MHz
  • Watchdog oscillator with a frequency range of 6 kHz to 1.5 MHz
  • 32 kHz low-power RTC oscillator
  • System PLL allows CPU operation up to the maximum CPU rate without the need for a high-frequency external clock. Maybe run from the internal FRO 12 MHz output, the external clock input CLKIN or the RTC oscillator
  • Clock output function with divider that can reflect many internal clocks
  • Frequency measurement unit for measuring the frequency of an on-chip or off-chip clock signal

Power Control

  • Integrated power management unit (PMU) to minimize power consumption
  • Reduced power modes: sleep mode, deep-sleep mode and deep power-down mode
  • Wake-up from deep-sleep mode on activity on USART, SPI and I2C peripherals when operating as followers
  • Wake-up from sleep, deep-sleep and deep power-down modes from the RTC alarm
  • The micro-tick timer can wake-up the device from a majority of reduced power modes by using the watchdog oscillator when no other on-chip resources are running, for ultra-low power wake-up
  • Power-On Reset (POR)
  • Brownout detect

Additional Information

  • Single power supply 1.62 V to 3.6 V
  • JTAG boundary scan supported
  • Serial wire debug (SWD) with 4 breakpoints and 2 watchpoints
  • Unique device serial number for identification
  • Operating temperature range of -40 °C to +105 °C
  • Available as LQFP64 and LQFP48 packages

Part numbers include: LPC51U68JBD48, LPC51U68JBD64.


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