Specifications

V850E2/MN4 USB CDC (Communication Device Class) Driver
R01AN0010EJ0101 Rev.1.01 Page 12 of 117
Feb 01, 2012
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Class Requests
Class requests are unique to the device class. Response processing for class requests corresponding to the CDC abstract
control model is implemented in the sample driver. The sample driver can respond to the following requests.
• Send Encapsulated Command
This request is used to issue commands in the communication class interface control protocol format.
• Get Encapsulated Command
This request requests a response in the communication class interface control protocol format.
• Set Line Coding
This request specifies the communications format for the serial communication.
• Get Line Coding
This request is used to acquire the current communication format setting at the device.
• Set Control Line State
This request is used for the RS-232/V.24 format control signals.
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Vendor Requests
The vendor requests are defined uniquely by the individual vendors. A vendor who is to use a vendor request needs to
provide a host driver that handles that request. A request is a vendor request when bit 6 of the bmRequestType field is
set to 1 and bit 5 to 0.
3.4.2 Format
A USB request is 8 bytes long and consists of the fields that are listed in the table below.
Table 3.3 USB Request Format
Offset Field Description
0 bmRequestType Request attribute
Bit 7 Data transfer direction
Bits 6 and 5 Request type
Bits 4 to 0 Target descriptor
1 bRequest Request code
2 wValue Lower
3 Upper
Arbitrary value used in the request
4 wIndex Lower
5 Upper
Index or offset used in the request
6 wLength Lower Number of bytes to transfer in data stage (data length)
7 Upper