USB to Serial Adapter

Introduction

This adapter allows connecting micro-controller boards that have 5V or 3.3V serial interfaces to a PC USB port. The converter is compatible with FTDI USB TTL Serial cables and SparkFun FTDI Basic breakout board. Compared to SparkFun board, uses much more reliable and common nowadays Micro USB connector. It is also cheaper to make (about $7 per board), and so it makes a nice project for practicing your SMD soldering skills :-).

Description

The board is based on FTDI FT231X chip. It provides RS-232 RX and TX signals, as well as DTR and CTS signals that are used by Arduino-like boards for resetting the microcontroller before uploading the code. The board schematic is available in the file section at the bottom of this page.

The board supports either 5V or 3.3V logic levels. It is pre-configured for 5V. To configured for 3.3V cut the trace between pins 2 and 3 of JP1/PWR_SEL on the bottom side of the board, and connect pins 1 and 2 together.

Bill of Materials

Link to the project on Mouser.com - View and order all components except of PCB.

Link to the project on OSHPark.com - View and order PCB.

Component type	Reference	Description	Quantity	Possible sources and notes
PCB		USB to Serial Adapter PCB	1	Order from OSH Park or from other PCB manufacturer. Download Gerber files are at the bottom of this page.
Capacitor	C1, C2	47pF capacitor, 0603 SMT	2	Mouser 77-VJ0603A470JXACBC
Capacitor	C3, C4	100nF capacitor, 0603 SMT	2	Mouser 77-VJ0603Y104JXJPBC
Capacitor	C5	10uF capacitor, 0805 SMT	1	Mouser 77-VJ0805G106KXQTBC
LED	D1	Green LED, 0603 SMT	1	Mouser 78-VLMG1300-GS08
LED	D2	Red LED, 0603 SMT	1	Mouser 78-VLMS1300-GS08
Connector	P1	Micro USB type B receptacle	1	Mouser 649-10118194-0001LF
Connector	P2	6 pin, 0.1" receptacle	1	Mouser 517-9601066303AR
Resistor	R1, R2	27 ohm resistor, 0603 SMT	2	Mouser 71-CRCW0603-27-E3
Resistor	R3, R4	1 kohm resistor, 0603 SMT	2	Mouser 71-CRCW0603-1.0K-E3
Integrated Circuit	U1	FTDR FT231XS	1	Mouser 895-FT231XS-R