What are the advantages and disadvantages of using PIC 18F4550 with USB interface?

2 Programming and Debugging

Another advantage of using PIC 18F4550 with USB interface is that it makes programming and debugging easier and faster. You can use the USB bootloader feature to load your firmware into the chip without an external programmer, saving you time and money. You can also use the USB interface to communicate with your PC or other devices for debugging purposes, using tools such as MPLAB X IDE, PICkit, or HyperTerminal. You can send and receive commands, data, or messages, and monitor the status of your application.

3 Memory and Performance

However, using PIC 18F4550 with USB interface also has some drawbacks that you should be aware of. One of them is the limited memory and performance of the chip. The PIC 18F4550 has 32 KB of flash memory, 2 KB of RAM, and 256 bytes of EEPROM. This might not be enough for some complex or data-intensive USB applications, especially if you use the M-USB library, which consumes a significant amount of memory and CPU cycles. You might need to optimize your code, reduce your buffer sizes, or use external memory devices to overcome this limitation.

4 Power and Compatibility

Another drawback of using PIC 18F4550 with USB interface is the power and compatibility issues that might arise. The PIC 18F4550 requires a 5 V supply voltage, which is not compatible with some low-power or battery-operated devices. You might need to use a voltage regulator or a boost converter to provide the necessary voltage. Moreover, the PIC 18F4550 does not support USB 2.0 high-speed mode, which limits its data transfer rate to 12 Mbps. This might not be a problem for most USB applications, but it might affect the performance or compatibility of some devices that require higher speeds, such as cameras, audio, or video.

5 Tips and Tricks

To make the most of using PIC 18F4550 with USB interface, you should refer to the PIC18F4550 datasheet and M-USB user guide for USB module features and functions. Additionally, you can use the Microchip Application Libraries (MAL) and Microchip Application Notes (AN) as templates for various USB applications and classes. The MPLAB Code Configurator (MCC) tool can be used to generate and configure the USB module settings and code, while the MPLAB Harmony 3 framework can help simplify and modularize your USB application development. Additionally, you can use the Microchip Device Firmware Upgrade (DFU) tool to update your firmware over USB without a bootloader, or the Microchip USB Device - HID - Custom Demo as a starting point for creating your own custom USB device class.