# USB Design Standpoint: On-Chip USB vs. Dedicated Chip

Soon enough, I will be facing a decision on implementing USB into one of our products. At first, I though that programming USB device and host drivers won't be that much of a problem, but it seems I was dead wrong.

A few days ago, I stumbled upon some pretty cool FTDI chips, that provide an interface which I can connect to easily on both ends. And since the additional price ($2) for such little QFN is not an issue, I am seriously considering this option. They also provide some pretty cool host-side WHQL-signed drivers that we can(?) use. Namely, it is 1. VCP (Virtual Com Port) driver, 2. D2XX driver, providing a DLL based application-USB interface. My question is, can anybody direct me either way? That is - will I make my life an order of magnitude easier by using an FTDI chip, or will I run into some wall that I'm not seeing right now? Thanks for sharing any experience. • I would say, Prefer FTDI Chips... Because You need to configure lot of Descriptors for Getting your device detected on PC... Plus, You will need Drivers on PC.... On other hand, FTDI comes with own drivers so you don't need to re-invent the wheel... And data is available on UART! – Swanand Jan 24 '14 at 11:48 • any other requirements, i feel speed at which data travels on other side of USB will have more variation when you go for Dedicated chips like USB-to-UART, USB to Parallel interface etc – user19579 Jan 24 '14 at 11:57 • Speed is not a requirement. User-friendliness and ease of use are the keys. – Dzarda Jan 24 '14 at 12:27 ## 1 Answer If your existing microcontroller doesn't have USB support (and good example drivers), and it can't easily be changed to one, and your volume is small enough that it's not worth saving the$2, then the FTDI chips are a very good solution.

• Thanks for your answer. The entire device is in scratch phase, that is, the microcontroller is not known yet. And the volume is literally like 3 units. – Dzarda Jan 24 '14 at 13:09
• In that case, consider the cables: ftdichip.com/Products/Cables/USBTTLSerial.htm and you don't even have to layout & fit the chip (it's buried in the cable). Or consider NXP's solution with builtin USB firmware + free software: lpcware.com/content/project/nxp-peripherals/… – pjc50 Jan 24 '14 at 13:46
• Thank you very much! Cables sound interesting, although I'd rather not supply an additional part to the customer. Embedding the FTDI chip sounds like a better solution. However, those NXP parts look neat! I'm mostly an Atmel guy, but discovery is part of research, isnt it :) – Dzarda Jan 24 '14 at 14:03