XR21V1414IM48 EXAR [Exar Corporation], XR21V1414IM48 Datasheet - Page 9

• Manufacturer Part Number: XR21V1414IM48
• Description: 4-CH FULL-SPEED USB UART
• Manufacturer: EXAR [Exar Corporation]

REV. 1.0.0
The I2C address should be 0xA0. An EEPROM can be used to override default Vendor IDs and Device IDs, as
well as other attributes and maximum power consumption. The EEPROM must contain 8 bytes of data as
specified in
These values are uploaded from the EEPROM to the corresponding USB Standard Device Descriptor or
Standard Configuration Descriptor. For details of the USB Descriptors, refer to the USB 2.0 specifications.
The Vendor ID value replaces the idVendor field in the USB Standard Device Descriptor.
The Product ID value replaces the idProduct field in the USB Standard Device Descriptor.
The Device Attributes value replaces the bmAttributes field in the USB Standard Configuration Descriptor.
The Device Maximum Power value replaces the bMaxPower field in the USB Standard Configuration
Descriptor.
The UART Manager enables/disables each UART including the TX and RX FIFOs for each UART. The UART
Manager is located in a separate register block from the 4 UART channels.
There are 4 enhanced UART channels in the V1414. Each UART channel is independent, therefore, they will
need to be initialized and configured independently. Each UART can be configured via USB control transfers
from the USB host.
The transmitter consists of a 128-byte TX FIFO and a Transmit Shift Register (TSR). Once a bulk-out packet
has been received and the CRC has been validated, the data bytes in that packet are written into the TX FIFO
of the specified UART channel. Data from the TX FIFO is transferred to the TSR when the TSR is idle or has
completed sending the previous data byte. The TSR shifts the data out onto the TX output pin at the data rate
defined by the CLOCK_DIVISOR and TX_CLOCK_MASK registers.
followed by the data bits (starting with the LSB), inserts the proper parity-bit if enabled, and adds the stop-
bit(s). The transmitter can be configured for 7 or 8 data bits with parity or 9 data bits with no parity.
1.3
1.4
1.2.1
1.2.1.1
1.2.1.2
1.2.1.3
1.2.1.4
1.4.1
EEPROM
A
DDRESS
0
1
2
3
4
5
6
7
UART Manager
UART
EEPROM Contents
Transmitter
Table 2
Vendor ID
Product ID
Device Attributes
Device Maximum Power
Signature of 0x58 (’X’). If the signature is not correct, the contents of the EEPROM are ignored.
T
ABLE
2: EEPROM C
Device Maximum Power
Product ID (MSB)
Vendor ID (MSB)
Product ID (LSB)
Device Attributes
Vendor ID (LSB)
9
C
Reserved
ONTENTS
ONTENTS
The transmitter sends the start bit
4-CH FULL-SPEED USB UART
XR21V1414