xr21b1411 Exar Corporation, xr21b1411 Datasheet - Page 13

• Manufacturer Part Number: xr21b1411
• Description: Enhanced 1-ch Full-speed Usb Uart
• Manufacturer: Exar Corporation

REV. 1.1.0
Note that all register reset default values are ’0’ unless otherwise specified.
CUSTOM_DRIVER[0]: Active
This register holds the flag to determine which device driver is used (custom or CDC driver). For proper
operation, a custom driver must set the ACTIVE bit prior to sending any of the 4 CDC_ACM commands that
the B1411 supports.
CUSTOM_DRIVER[11:1]: Reserved
These bits are reserved and should remain ’0’.
The contents of this register, if programmed, are used to overwrite the FLOW_CONTROL register at address
0xC06 when a CDC command is sent from a standard CDC-ACM driver to the B1411 device. Note that this
register can only be programmed from the OTP. Since a standard CDC_ACM driver is unaware of UART
registers in the B1411, this register may be utilized to program UART settings from power-up. When a custom
driver is used, the custom driver should program these settings directly into the FLOW_CONTROL register.
Bit fields in this register are the same as those in the FLOW_CONTROL register. Refer to
FLOW_CONTROL Register Description (Read / Write)” on page
A
3.1.1
3.1.1.1
3.1.1.2
0XCC0 RX_FIFO_RESET
0XC80 TX_FIFO_RESET
0xCC1 RX_FIFO_COUNT
0xCC2 RX_FIFO_LOW_LA
0xC12
0xC14
0xC15
0xC16
0xC81
0xD02
0xC11
DDRESS
Logic 0 = Informs the B1411 that the standard CDC_ACM driver is being used. Values from the
CDC_ACM_xxx_xxxx registers will be loaded into their non-CDC_ACM equivalents.
Logic 1 = Informs the B1411 that a custom driver is being used. Values from CDC_ACM_xxx_xxxx
registers are not used.
GPIO_INT_MASK
CUSTOMIZED_INT
PIN_PULLUP_EN
PIN_PULLDOWN_
EN
LOOPBACK
TX_FIFO_COUNT
TENCY
WIDE_MODE
B1411 Register Descriptions
R
EGISTER
CUSTOM_DRIVER (Write Only)
CDC_ACM_FLOW_CONTROL Register Description (Read / Write)
N
AME
B
IT
0
0
0
0
0
0
0
0
0
0
0
-11
B
10
0
0
0
0
0
0
0
0
0
0
0
IT
-
T
ABLE
B
IT
0
0
0
0
0
0
0
0
0
0
0
-9 B
5: B1411 R
IT
0
0
0
0
0
0
0
0
0
0
-8 B
13
TX
TX
IT
0
0
0
0
0
0
0
-7 B
EGISTERS
ENHANCED 1-CH FULL-SPEED USB UART
RX
RX
IT
0
0
0
0
0
0
0
-6 B
15.
GPIO
GPIO
GPIO
IT
5
0
5
5
0
0
0
0
0
-5 B
COUNT
GPIO
GPIO
GPIO
IT
4
0
4
4
0
0
0
0
0
COUNT
-4
GPIO
GPIO
GPIO
B
IT
3
0
3
3
0
0
0
0
0
-3
DTR_
GPIO
GPIO
GPIO
B
DSR
IT
“Section 3.1.1.7,
2
0
2
2
0
0
0
0
XR21B1411
-2 B
RTS_
GPIO
GPIO
GPIO
CTS
IT
1
0
1
1
0
0
0
0
-1 B
GPIO
GPIO
GPIO
TX_
EN
RX
RX
EN
EN
TX
IT
0
0
0
-0