Datasheet

321
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
For more details about VID/PID for End Product/Systems, please refer to the Vendor ID form available from the
USB Implementers Forum on www.usb.org.
Atmel provides an INF example to see the device as a new serial port and also provides another custom driver
used by the SAM-BA application: atm6124.sys. Refer to the application note Basic USB Application (Atmel
literature number 6123) for more details.
20.4.3.1 Enumeration Process
The USB protocol is a master/slave protocol. This is the host that starts the enumeration sending requests to the
device through the control endpoint. The device handles standard requests as defined in the USB Specification.
The device also handles some class requests defined in the CDC class.
Unhandled requests are STALLed.
20.4.3.2 Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process. Endpoint 1 is a 64-
byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint. SAM-BA Boot commands are sent by the
host through endpoint 1. If required, the message is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the response.
20.4.4 In Application Programming (IAP) Feature
The IAP feature is a function located in ROM that can be called by any software application.
When called, this function sends the desired FLASH command to the EEFC and waits for the Flash to be ready
(looping while the FRDY bit is not set in the EEFC_FSR).
Since this function is executed from ROM, this allows Flash programming (such as sector write) to be done by
code running in Flash.
The IAP function entry point is retrieved by reading the NMI vector in ROM (0x00100008).
This function takes one argument in parameter: the command to be sent to the EEFC.
This function returns the value of the EEFC_FSR.
Table 20-2. Handled Standard Requests
Request Definition
GET_DESCRIPTOR Returns the current device configuration value.
SET_ADDRESS Sets the device address for all future device access.
SET_CONFIGURATION Sets the device configuration.
GET_CONFIGURATION Returns the current device configuration value.
GET_STATUS Returns status for the specified recipient.
SET_FEATURE Set or Enable a specific feature.
CLEAR_FEATURE Clear or Disable a specific feature.
Table 20-3. Handled Class Requests
Request Definition
SET_LINE_CODING Configures DTE rate, stop bits, parity and number of character bits.
GET_LINE_CODING Requests current DTE rate, stop bits, parity and number of character bits.
SET_CONTROL_LINE_STATE RS-232 signal used to tell the DCE device the DTE device is now present.