The USB CDC driver for Atmel SAM ARM microcontrollers allows a USB microcontroller that is running the SAM-BA software to be configured as a virtual COM port on a PC.
This allows user software to be loaded to the microcontroller via a USB cable using the SAM-BA PC application software.
The article on Installing the SAM-BA USB CDC Driver for Atmel ARM Microcontroller in Windows shows how to install and test the driver.
Terminal emulator software is used to communicate with the embedded SAM-BA software on the microcontroller and request the SAM-BA software version number. This is done to test that the driver and connections are working properly.
AT91SAM7S microcontrollers can be programmed via the USB port — no programming device is necessary. This tutorial explains how to program the AT91SAM7S256 microcontroller on a AT91SAM7S-EK evaluation board over the USB port using the SAM-BA in-system programming software from Atmel.
The tutorial includes information on where to download the SAM-BA software from and a video on how to load firmware to the AT91SAM7S microcontroller.
AT91SAM7S ARM7 microcontrollers have a built in boot loader program called SAM-BA that allows them to be programmed in-circuit via the USB port without the need for an external programmer. This article explains what the hardware requirements are in order to use SAM-BA.