XR21V1410IL-0A-EB Datasheet, PDF (5/28 Pages) Exar Corporation – 1-CH FULL-SPEED USB UART

XR21V1410
REV. 1.3.0
1-CH FULL-SPEED USB UART
1.0 FUNCTIONAL DESCRIPTIONS
1.1 USB interface
The USB interface of the V1410 is compliant with the USB 2.0 Full-Speed Specifications. The USB
configuration model presented by the V1410 to the device driver is compatible to the Abstract Control Model of
the USB Communication Device Class (CDC-ACM). The V1410 uses the following set of parameters:
• 1 Control Endpoint
s Endpoint 0 as outlined in the USB specifications
• 1 Configuration is supported
• 2 interfaces for the UART channel
s Single interrupt endpoint
s Bulk-in and bulk-out endpoints
1.1.1 USB Vendor ID
Exar’s USB Vendor ID is 0x04E2. This is the default Vendor ID that is used for the V1410 unless a valid
EEPROM is present on the I²C interface signals. If a valid EEPROM is present, the Vendor ID from the
EEPROM will be used.
1.1.2 USB Product ID
The default USB Product ID for the V1410 is 0x1410. If a valid EEPROM is present, the Product ID from the
EEPROM will be used.
1.2 USB Device Driver
The V1410 device can be used with either a standard CDC-ACM driver or a custom driver. When the CDC-
ACM driver is used, the driver has no knowledge of the V1410 device registers. Because of this, the V1410
device is initialized to the following settings:
TABLE 1: V1410 REGISTER DEFAULTS WITH CDC-ACM DRIVER
REGISTER
VALUE
NOTES
FLOW_CONTROL
0x01
Hardware flow control
GPIO_MODE
0x01
RTS / CTS flow control
GPIO_DIRECTION
0x08
DTR configured as an output (in addition to RTS which is set by
GPIO_MODE)
GPIO_INT_MASK
0x30
CD and DSR are interrupt sensitive, i.e. can cause a USB inter-
rupt to be generated
Note that when using a CDC-ACM driver, the V1410 will automatically change the bMaxPacketSize to 63 bytes
to compensate for a known issue with the Microsoft CDC-ACM device driver. A register is available to change
this setting with a custom driver as well. See “Section 3.4.1, CUSTOM Register Description (Read/Write)”
on page 22 and “Section 1.5.2.1, Wide mode Receive” on page 7.
5