3.5.8 UART/USB Bridge Interface

UART0 of ATSAM4CMS16C is user accessible by means of micro USB type B connector (J9). A single chip bridge, MCP2200 device, is used to convert the UART signal to USB levels to ease PC connectivity (USB 2.0, full speed) for debugging purposes.

A high speed optocoupler provides isolation between the PCB signals and your PC. This lets you connect the USB cable when you are using metrology circuit or an PLCOUPxxx board not isolated from mains.

Figure 3-35. Debug UART over USB Circuit

Important: Check weblink to download the drivers according to your Operative System.

Furthermore, UART0 and UART1 as TTL level signals (3.3 V) are also available in a triple row male connector (J5). If this interface is used, USB port (J9) must remain unconnected to avoid collisions on UARTs signals.

Figure 3-36. Debug UARTs over 3.3 Volts Levels

CAUTION: This connector is not isolated from mains. Please make use of proper isolation (i.e.: USB isolator device) in case of debugging when the board is not galvanically isolated (metrology circuit measurements or using an PLCOUPxxx board which it is not isolated from mains).