I'm using the Arty A7-35 board and have been going through the tutorials and built a MicroBlaze soft processor with a UartLite serial port using Vivado 2018.3 on Ubuntu 18.04 LTS. It did not work! Looking through the Arty A7 Reference Manual I found this:
Quote
After the drivers are installed, I/O commands can be used from the PC directed to the COM port to produce serial data traffic on the A9 and D10 FPGA pins.
Two on-board status LEDs provide visual feedback on traffic flowing through the port: the transmit LED (LD10) and the receive LED (LD9). Signal names that imply direction are from the point-of-view of the DTE (Data Terminal Equipment), in this case the PC.
and looking at this diagram:
Then the Artix-7 A9 pin should be configured as an input and the D10 pin as output.
But here is the usb_uart interface spec in the ./board_files/arty-a7-35/E.0/board.xml file :
<interfacemode="master"name="usb_uart"type="xilinx.com:interface:uart_rtl:1.0"of_component="usb_uart"preset_proc="uart_preset"><preferred_ips><preferred_ipvendor="xilinx.com"library="ip"name="axi_uartlite"order="0"/></preferred_ips><port_maps><port_maplogical_port="TxD"physical_port="usb_uart_txd"dir="out"><!--Change to “in”--><pin_maps><pin_mapport_index="0"component_pin="usb_uart_txd"/></pin_maps></port_map><port_maplogical_port="RxD"physical_port="usb_uart_rxd"dir="in"><!--Change to “out”--><pin_maps><pin_mapport_index="0"component_pin="usb_uart_rxd"/></pin_maps></port_map></port_maps></interface>
So, usb_uart_txd should be "in", usb_uart_rxd should be "out". When I change this, the UartLite serial port works! I tried to change the direction of the pins in the Project HDL "wrapper" to no avail. Please note that this default config is found in the board.xml files for arty, arty-A7 and arty-S7. Do the board.xml files need to be changed? Is there some other way to change pin direction in the Vivado Project?
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CaptIgmu
I'm using the Arty A7-35 board and have been going through the tutorials and built a MicroBlaze soft processor with a UartLite serial port using Vivado 2018.3 on Ubuntu 18.04 LTS. It did not work! Looking through the Arty A7 Reference Manual I found this:
and looking at this diagram:
Then the Artix-7 A9 pin should be configured as an input and the D10 pin as output.
But here is the usb_uart interface spec in the ./board_files/arty-a7-35/E.0/board.xml file :
So, usb_uart_txd should be "in", usb_uart_rxd should be "out". When I change this, the UartLite serial port works! I tried to change the direction of the pins in the Project HDL "wrapper" to no avail. Please note that this default config is found in the board.xml files for arty, arty-A7 and arty-S7. Do the board.xml files need to be changed? Is there some other way to change pin direction in the Vivado Project?
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