MaxLinear XR21B1420IL28-0A-EVB USB to RS-232/422/485 Evaluation Board
Overview
USB to serial evaluation board. Supports RS-232, RS-422, and RS-485. Made by MaxLinear, formerly Exar. Supposedly supports higher than usual baudrates, up to 12Mbaud.
MaxLinear XR21B1420IL28-0A-EVB | DigiKey
MaxLinear XR21B1420IL28-0A-EVB | Mouser
Wiring Diagram
| DB9 Pin | RS-232 | RS-422 | RS-485 |
|---|---|---|---|
| 1 | DCD | TX- | Data- |
| 2 | RXD | TX+ | Data+ |
| 3 | TXD | RX+ | |
| 4 | DTR | RX- | |
| 5 | (GND) | ||
| 6 | DSR | ||
| 7 | RTS | ||
| 8 | CTS | ||
| 9 | RI | ||
- Page 5 of the SP339E datasheet shows the DE9 pinout
Software
To get full functionality under Linux, you must install the xr_usb_serial_common kernel module. The drivers are available here:
In the "USB UART" section in their downloads table, pick the latest version for Linux. Here is a direct link to version 1C for "Linux 3.6.x and newer":
xr_usb_serial_common_lnx-3.6-and-newer-pak.zip
If successfully installed, when the USB device (04e2:1420 Exar Corp.) is connected it the device node /dev/ttyXRUSB0 should show up.
Bill of Materials
| Name | Part |
|---|---|
| U2 | MaxLinear SP339ECR1-L |
| U3 | MaxLinear XR21B1420IL28-F |
Online Resources
Exar XR21B1420IL28-0A-EVB Evaluation Board User’s Manual Rev 1A
Exar XR21B1420/21 Evaluation Board Schematic Rev 1.0
Exar XR21B1420IL28-0A-EVB Evaluation Board User’s Manual Rev 1A
Exar XR21B1420/21 Evaluation Board Schematic Rev 1.0