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| | | |
| [https://www.mouser.com/ProductDetail/MaxLinear/XR21B1420IL28-0A-EVB?qs=C8E66ftkQtzee90NEaObRg%3D%3D MaxLinear XR21B1420IL28-0A-EVB | Mouser] | | [https://www.mouser.com/ProductDetail/MaxLinear/XR21B1420IL28-0A-EVB?qs=C8E66ftkQtzee90NEaObRg%3D%3D MaxLinear XR21B1420IL28-0A-EVB | Mouser] |
| + | |
| + | == Wiring Diagram == |
| + | |
| + | {| class="wikitable" |
| + | ! DB9 Pin |
| + | ! RS-232 |
| + | ! RS-422 |
| + | ! RS-485 |
| + | |- |
| + | | 1 |
| + | | DCD |
| + | | TX- |
| + | | Data- |
| + | |- |
| + | | 2 |
| + | | RXD |
| + | | TX+ |
| + | | Data+ |
| + | |- |
| + | | 3 |
| + | | TXD |
| + | | RX+ |
| + | | |
| + | |- |
| + | | 4 |
| + | | DTR |
| + | | RX- |
| + | | |
| + | |- |
| + | | 5 |
| + | | colspan="3" | (GND) |
| + | |- |
| + | | 6 |
| + | | DSR |
| + | | |
| + | | |
| + | |- |
| + | | 7 |
| + | | RTS |
| + | | |
| + | | |
| + | |- |
| + | | 8 |
| + | | CTS |
| + | | |
| + | | |
| + | |- |
| + | | 9 |
| + | | RI |
| + | | |
| + | | |
| + | |} |
| + | |
| + | * [https://www.maxlinear.com/ds/sp339e.pdf#page=5 Page 5] of the SP339E datasheet shows the DE9 pinout |
| + | |
| + | == Jumpers == |
| + | |
| + | {| class="wikitable" |
| + | ! Name |
| + | ! Default |
| + | ! Function |
| + | |- |
| + | | J2 |
| + | | 1 & 2 (down) |
| + | | 1 & 2 (down): VCC_OUT to VCC_TRANS<br/>2 & 3 (up): VCC_USB to VCC_TRANS |
| + | |- |
| + | | J3 |
| + | | |
| + | | pins map to DE9 connector, except pin 5 (GND) is skipped |
| + | |- |
| + | | J4 |
| + | | |
| + | | 47k pull-ups to VCC_TRANS for jumpering to J18 |
| + | |- |
| + | | J10 |
| + | | 1 & 2 (right) |
| + | | 1 & 2 (right): VCC_USB to VCC_UART<br/>2 & 3 (left): VCC_3V3 to VCC_UART |
| + | |- |
| + | | J11 |
| + | | (not present) |
| + | | 1 & 2 (left): VCC_OUT to VIO<br/>2 & 3 (right): VIO_EXTERNAL to VIO |
| + | |- |
| + | | J12 |
| + | | 1 & 2 (down) |
| + | | 1 & 2 (down): GPIO7/!RI/!RWK to SW1 button<br/> 2 & 3 (up): GPIO7/!RI/!RWK to !RI_TRANS |
| + | |- |
| + | | J13 |
| + | | 2 & 3 (left) |
| + | | 1 & 2 (right): VIO to VCC<br/>2 & 3 (left): VCC_OUT to VCC |
| + | |- |
| + | | J15 |
| + | | 2 & 3 (up) |
| + | | 1 & 2 (down):<br/>2 & 3 (up) |
| + | |- |
| + | | J17 |
| + | | 2 & 3 (up) |
| + | | 1 & 2 (down): TXT_MODE1 to TXT<br/>2 & 3 (up): pullup/D1 LED to TXT |
| + | |- |
| + | | J18 |
| + | | ??? |
| + | | TODO |
| + | |- |
| + | | J19 |
| + | | (not present) |
| + | | 1 & 2: connects the regulated 3.3V from the SP6260 to the VCC pin of the XR21B1420 |
| + | |- |
| + | | J20 |
| + | | 1 & 2 |
| + | | 1 & 2: GPIO9/!DSR to !DSR (transceiver) NOTE: manual claims GPIO2? schematic says GPIO9... |
| + | |- |
| + | | J21 |
| + | | |
| + | | 1 & 2 (down): XEN to J37 pin 3 <br/>2 & 3 (up): !RTS_XEN to J37 pin 3 |
| + | |- |
| + | | J23 |
| + | | |
| + | | ...<br/>3 & 4: VCC_USB to !RESET</br>... |
| + | |- |
| + | | J24 |
| + | | |
| + | | (various debug signals) |
| + | |- |
| + | | J37 |
| + | | |
| + | | ...<br/>3 & 4 (2nd from left): XEN or !RTS_XEN to DIR1</br>... |
| + | |} |
| + | |
| + | == Software == |
| + | |
| + | To get full functionality under Linux, you must install the <code>xr_usb_serial_common</code> kernel module. The drivers are available here: |
| + | |
| + | [https://www.maxlinear.com/support/design-tools/software-drivers Software Drivers - MaxLinear] |
| + | |
| + | In the "USB UART" section in their downloads table, pick the latest version for Linux. Here is a direct link to version 1D for "Linux 3.6.x and newer": |
| + | |
| + | [https://assets.maxlinear.com/web/documents/xr_usb_serial_common_lnx-3.6-and-newer-pak_v1d.zip xr_usb_serial_common_lnx-3.6-and-newer-pak_v1d.zip] |
| + | |
| + | <del>[https://www.maxlinear.com/content/document.ashx?id=21651 xr_usb_serial_common_lnx-3.6-and-newer-pak.zip]</del> (1C was superseded by 1D) |
| + | |
| + | If successfully installed, when the USB device (<code>04e2:1420 Exar Corp.</code>) is connected it the device node <code>/dev/ttyXRUSB0</code> should show up. |
| + | |
| + | == Bill of Materials == |
| + | |
| + | {| class="wikitable" |
| + | ! Name |
| + | ! Part |
| + | |- |
| + | | U2 |
| + | | [https://www.digikey.com/product-detail/en/maxlinear-inc/SP339ECR1-L/1016-1703-ND/2770686 MaxLinear SP339ECR1-L] |
| + | |- |
| + | | U3 |
| + | | [https://www.digikey.com/product-detail/en/maxlinear-inc/XR21B1420IL28-F/1016-2063-ND/5080590 MaxLinear XR21B1420IL28-F] |
| + | |} |
| | | |
| == Online Resources == | | == Online Resources == |
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| | | |
| [https://www.maxlinear.com/ds/xr21b1420.pdf MaxLinear XR21B1420 Datasheet] | | [https://www.maxlinear.com/ds/xr21b1420.pdf MaxLinear XR21B1420 Datasheet] |
| + | |
| + | [https://www.maxlinear.com/ds/sp339e.pdf MaxLinear SP339E Datasheet] |
| + | |
| + | [https://www.maxlinear.com/product/interface/uarts/usb-uarts/xr21b1420 XR21B1420 - MaxLinear] |
| | | |
| <del>[http://www.bdtic.com/download/exar/21623 Exar XR21B1420IL28-0A-EVB Evaluation Board User’s Manual Rev 1A]</del> | | <del>[http://www.bdtic.com/download/exar/21623 Exar XR21B1420IL28-0A-EVB Evaluation Board User’s Manual Rev 1A]</del> |