XR21B1420IL28-0A Datasheet, PDF (42/60 Pages) Exar Corporation – Enhanced 1-Ch Full-Speed USB UART

XR21B1420
Bit
2:0
Default
Description
0
GPIO Mode Select
000: GPIO. RTS/CTS and DTR/DSR are used for general purpose I/O.
001: RTS_CTS. GPIO4 and GPIO5 used for Auto RTS/CTS HW Flow Control
010: DTR_DSR. GPIO2 and GPIO3 used for Auto DTR/DSR HW Flow Control
011: RS485_EN_ACT. GPIO5/RTS#/RS485 pin used for auto .RS-485 half-duplex enable during Transmit
100: RS485_EN_FLOW. GPIO5/RTS#/RS485 pin used for auto RS-485 half-duplex enable after address
match.
101 to 111: Reserved. Reserved value, do not use.
CDC_ACM_MODE_MSB (0x00A) - Read/Write OTP
Bit
7:2
1
0
Default
Description
0
Reserved
These bits are reserved and should be written as ‘0’.
1
Receive Toggle
0: GPIO9 is used for general purpose I/O
1: GPIO9 is used to receive toggle output (default).
1
Transmit Toggle
0: GPIO8 is used for general purpose I/O.
1: GPIO8 is used to transmit toggle output (default).
CDC_ACM_GPIO_DIR_LSB (0x00B) - Read/Write OTP
Bit
7:0
Default
0
GPIO Direction of GPIO[9:0]
0: GPIOx is an input.
1: GPIOx is an output.
Description
CDC_ACM_GPIO_DIR_MSB (0x00C) - Read/Write OTP
Bit
7:2
1:0
Default
0
Reserved
These bits are reserved and should be ‘0.’
0
GPIO Direction of GPIO[9:0]
0: GPIOx is an input.
1: GPIOx is an output.
Description
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exar.com/XR21B1420
Rev 1A