The LPC1768 USB device, built on the ARM Cortex-M3 processor, is a widely used microcontroller in embedded USB applications that require real-time performance and rich connectivity. One of its strongest features is the integrated USB controller supporting USB 2.0 full-speed device, host, and OTG modes. This makes the LPC1768 USB interface suitable for applications such as data logging, firmware updates, HID devices, mass storage devices, and USB-based communication systems.
In modern embedded systems USB designs, USB connectivity has become a primary requirement for device configuration, communication with PCs, and plug-and-play operation. With the LPC1768 USB device, developers can implement reliable USB functionality without using external USB controllers, thereby reducing system cost and improving design efficiency.
USB device interfacing with ARM Cortex-M3 LPC1768 enables reliable USB communication in embedded systems using its built-in USB 2.0 full-speed controller. This guide covers hardware setup, USB modes, clock configuration, descriptors, endpoints, and class-specific implementation, helping engineers build stable and production-ready USB-enabled embedded applications.
should understand before building professional embedded applications.
The LPC1768 ARM Cortex-M3 microcontroller includes an integrated USB 2.0 Full-Speed controller designed for reliable embedded USB communication in device, host, and OTG applications.
The LPC1768 USB device supports several standard USB classes commonly used in embedded systems:
Since the USB transceiver is integrated, only minimal external hardware is required to enable the USB interface.
To implement USB device interfacing using LPC1768, the following hardware components are required:
| USB Signal | LPC1768 Pin |
|---|---|
| D+ (DP) | P0.29 |
| D− (DM) | P0.30 |
| VBUS | P1.30 |
| USB_UP_LED | P1.18 |
| USB_CONNECT | P2.9 |
The LPC1768 USB controller supports three operational modes:
Allows automatic switching between USB host and device roles.
Most embedded USB projects using LPC1768 focus on USB Device Mode.
PINSEL1 |= (2 << 18) | (2 << 20); // P0.29, P0.30 = USB DP/DM PINSEL3 |= (1 << 4); // P1.30 = VBUS PINSEL4 |= (1 << 18); // P2.9 = USB_CONNECT
PCONP |= (1 << 31); // Enable USB PCLK USBClkCtrl = 0x12; // Enable device and AHB clocks
PLL1CFG = (1 << 0) | (3 << 5); PLL1FEED = 0xAA; PLL1FEED = 0x55; PLL1CON = 1; PLL1FEED = 0xAA; PLL1FEED = 0x55;
USBDevIntClr = 0xFFFFFFFF; USBDevIntEn = (1 << 2) | (1 << 3); // Enable EP0 interrupts
| Endpoint Type | Usage |
|---|---|
| Control (EP0) | Mandatory for enumeration |
| Bulk | CDC, Mass Storage |
| Interrupt | HID devices |
| Isochronous | Audio and streaming |
USB stacks such as Keil USB Stack, LPCOpen, and TinyUSB simplify USB programming for LPC1768.
USB device interfacing in ARM Cortex-M3 LPC1768 allows the microcontroller to communicate with a PC as a USB device for data transfer and control.
Yes, LPC1768 has an inbuilt USB 2.0 full-speed USB controller supporting device, host, and OTG modes.
LPC1768 supports USB device mode, USB host mode, and USB OTG mode.
A 48 MHz clock is required to meet USB full-speed timing requirements for reliable USB communication.
Yes, LPC1768 is beginner-friendly due to its built-in USB controller and good library support.
You can learn USB device interfacing with ARM Cortex-M3 LPC1768 through hands-on embedded systems training programs that cover USB programming, firmware development, and real-time project implementation.