DVM-V24 USB V24 Adapter

No more cisco routers and WIC cards! Now you can connect your quantar directly to a linked network without stacks of extra hardware. The DVM-V24 connects Quantars and other V24-capable equipment to the DVM Host (dvmhost) software.

Hardware

DVM-V24 boards are available from the W3AXL Online Store. Purchasing through W3AXL supports development efforts for the DVMProject team and future hardware projects!

Schematics for the board are also included in the hw directory to build your own adapters.

Hardware Revisions

There are two hardware revisions, the original "V1" boards, and the newer "V2" boards. The V2 boards offload the USB->serial functionality to a dedicated CP2102 chip which alleviates some lockup/freezing issues that were encountered with the original V1 hardware.

The two hardware revisions require different firmware binaries, but both can be built from the same repository and commands.

The CLKSEL Jumper

This jumper connects the serial clock line to the RXCLK pin. Currently this jumper must be in place for the V24 adapter to work properly. Version 1 boards require a jumper to be in place, while version 2 boards have the solder jumper shorted by default. In the future, the boards may support external clocking, but for now the firmware only supports generating clocks for both TX & RX.

UBT0 and URST Jumpers

These jumpers are specific to the version 2 boards and enable the RTS and DTR signals of the serial chip to force the board into UART bootloader mode. This will allow for programming using stm32flash even without access to the software boot command in dvmhost. By default these jumpers are not connected and must be bridged with solder to enable RTS/DTR boot control. Note that with these jumpers shorted, the V24 board will reset when dvmhost connects.

Firmware

Firmware is availble in this repo, under the fw directory. It's written in bare C, generated from STM32CubeMX. You will need an STLink programmer in order to flash the boards with the latest version of software.

Building the latest firmware

We recommend building the firmware for the DVM-V24 on a linux-based machine, since it's much easier to set up a working ARM toolchain.

On debian machines, you will need to install the following packages to build the fw:

sudo apt install gcc-arm-none-eabi cmake

Once you have the everything installed, perform the following steps to prepare the build environment:

mkdir build
cd build
cmake ..

Finally, you can build firmware individually for the v1 or v2 boards, or build both binaries:

# To build for V1 only:
make dvm-v24-v1
# or to build for V2:
make dvm-v24-v2
# make with no options will build both v1 and v2 binaries
make

Flashing the firmware

Using STLink programmer

You may use the SWD headers on the board to load firmware via an STLink programmer. This is required for the V1 boards, and on the V2 boards if the firmware becomes corrupted and USB loading no longer works.

First make sure the stlink-tools are installed on your system:

sudo apt install stlink-tools

Then you can flash the board by using the following command

st-flash --reset write dvm-v24-xxx.bin 0x8000000

Using USB flashing

DVMV24-V2 boards can be loaded using the ST serial bootloader, in the same way that DVM modems can. First, you must put the board into bootloader mode using dvmhost in calibration mode:

./dvmhost -c <config file.yml> --cal

Then, enter bootloader mode using the ! command. DVMHost will exit, and at this point you can use the stm32flash command:

stm32flash -v -w ./dvm-v24-v2.bin -R /dev/ttyUSBx

If you have the UBT0 and URST jumpers shorted, you can also flash the board using DTR & RTS in a single command as follows:

stm32flash -v -w ./dvm-v24-v2.bin -i 'rts&-dtr:-rts&dtr' /dev/ttyUSBx

Quick Start

Quantar V24 Connection

The DVM-V24 RJ45 is pinned out so that a straight-through RJ45 cable (i.e. any normal, non-crossover ethernet cable) can be used to connect to the Quantar's front wireline RJ45 connectors.

Pinout

Repeater Programming

The following are the relevant fields that need to be configured in Quantar RSS:

Field	Value
Wireline Operation	4 WIRE FULL DUPLEX
Astro To Wireline	ENABLED
Wireline Interface	V.24 ONLY
External Transmit Clock	ENABLED
RT/RT Configuration	DISABLED

dvmhost Configuration

dvmhost must be configured to operate in dfsi mode. Under modem, ensure the following parameters are set:

modem:
    protocol:
        type: "uart"
        mode: "dfsi"
        uart:
            port: /dev/ttyACM0 # change to your v24 board's serial port
            speed: 115200
    dfsi:
        rtrt: true
        diu: true
        jitter: 200

CCGW V24 Connection

We are still investigating compatibility with the CCGW's V24 port. In theory, it should be possible, however early tests have shown the CCGW in Quantar compatibility mode does not properly mirror the Quantar's V24 port behavior.

Support

Support is available on our Discord server - there are many users and project members online who can help with any issues you may encounter. Join here!