Extension Board for VIM - Audio/SPDIF/USB/GPIO - New Development

Hello Vim Users,

I’m like it VIM a much for few reasons but It’s missing here some card to offer more interfaces. I’m developed that and I’m guess I can share to everybody who is interest.

Feature list are:

  • Toslink SPDIF Optical Out Connector (no coax, just optical)
  • 2x USB 2.0 Port, with current limit 1.5A/ per port (used two free usb port)
  • Extra 2.1/2.5mm DC jack for 5V power in (USB C can be used as next USB port)
  • Controlled +5V/3.3V FAN by PWR_EN and GPIO PWM_F (turn off FAN, when system is off or GPIO)
  • Audio Chip with “Line Out” and “Mic In” as 3.5mm Jacks
  • Serial Port TX/RX to USB chip on board, for debugging and communications
  • Small EEPROM 24C64 (8Kbyte) for any user data/configurations
  • And last but not least 2x20Pin connectors supports Raspberry PI breakouts - more details later
  • same shape like VIM, so can be easily plugged in and fixed by screws.

With that boards, I’m believe you can run VIM finally with all full features set developed by Khadas :heart_eyes:

Price: 25$/24.5Euro (now) without shipment. I’m located in Germany and I’m able to ship goods around the world. I can make ebay item, but will prefer if we can makes payment out of ebay (I need pay 10% to ebay :frowning: ). Sorry no gearbest, aliexpress, etc.

Shipment price should be 5$/4.9Euro For many countries, for others different price (sorry, price is high, I know)

If I’m found that somebody is interest, I can provide better prices (but I need get interest for more than 30pcs) than price will be cheaper for 2$. Please sent me message or leave message here.

More specific details

2x USB Ports has each limiter 1.5A (no polyfuse, real limiter). I’m recommend use 2.1mm Adapter (5V/3A) or more to support full current flow. This will anyway enable to use USB-C for another purpose and not power the system. All peripherals are off when system is off (SPIDIF,USB,Audio,FAN,Raspberry). USB Over current can be watch by system, but only one signal shared for these two USB.

Input jack 5V, has 4A fuses and protective diodes, can support power for whole system and than no any others power is needed. Only +5V input is allowed (no +9-12V etc). Sorry no space.

Audio Chip is WM8731, chosen for support Mic IN, sorry no Headphones due space limitations. Line Out can be used only with amplifier or home PC speakers/receiver. There are two jack 3.5mm on board for easy connections. 96KHz only, but 100dB.

Serial Ports use PL2303SA, user can chose which serial port will goes to the USB. With MicroUSB you can connect host systems and watch/control the VIM. Chips was used due to the space and cost. There is additionally connector for FTDI-3.3-TTL cable adapter (can be directly connected, without modifications)

FAN connectors supports 1.00mm and 1.25mm connector. Can be chosen voltage by jumper. FAN is turnoff when power is off, or can be controlled by SW by GPIO PWM_F signal. By Default FAN is running on full speed.

Serial EEPROM AT24C64 can be used for any data needs to be stored permanently or for bootup .

Raspberry Connections is 2x20Pins with GPIO expander and I2C->SPI expander. This means, That I’m re-create full connections to support any raspberry boards what you can find in the market. Of course, there isn’t SW support for expander yet, but here community is fine, right? :wink: . So either GPIO and SPI interface isn’t supported now. Others signals like I2C, Serial Port, I2S are connected too.
Expander are MCP23017 and SC18IS602B. For example With ISP/i2C you can drive small display, etc…

There is universal 5V/3A Transistors for general purpose controlled by GPIO. Connector 2pin/2mm.

I can imagine that board can be entry point for more applications, or your project. Sorry for high price, components are expensive, what you can confirm by schematic check, but is for demo purposes. Due the open policy of VIM schematic, I would like follow that too :smiley:

Please, if you find any mistake in schematic, please let me know.

And one important things, design is ready, but first prototypes (min 10pcs) will be ordered soon. I’m just try figure your interest. So currently I’m cannot ship the boards. This will takes aprox. 5 weeks from now. So I haven’t nothing by hand yet. When prototypes will be ready and working I can ship that.

below, how board will looks like, the all components are from TOP and high of them should be more than 8mm for extensions board for raspberry PI. There are holes for Acrylic Cover (2mm) and internal 2mm for board without acrylic frame. Raspberry PI extensions can be hold in 3 holes. In the package should be 4x8mm spacer and 4x M2x30mm screws, what needs to be exchanged by previous screws to put all together.


P.S. I’m ok, if Khadas would take that and offer by yourself… Believe or not, there isn’t really big revenue for small players like me. But if I’m spend a time with that, I’m Like to support others.

  1. I am interested in Your development and I am willing to buy (pay for a pre-order, with the delivery in 5-6 weeks).
  2. Do You have the ability to create different configurations (a set of items / features) ?

Always Interested, i will add if it helps

Gute Nachrichten. Ich hätte das gekauft.

this is a brilliant idea and seem well thought.

I encourage you to go further,
I also would be ok to buy such an add-on board;

Winning ideas for me are

  • 5V connector more standard than the native one on the mainboard
  • spdif output
  • ability to be compatible with rpi hats

other hardware functions are less relevant for me.

And yes, let the community provide the code to deal with the new hardware and each rpi hat we want to support

We see that there is no plan from Kadas’ for expanding the current hardware during its lifetime, but your proposal could also help them to decide to include on the main board some of the most popular features of this add-on board.

1 Like

Hello Balbes, Ravelo and all,

thanks for interest, appreciated…

Balbes, about second point, can you be more specific with your questions?

Like add some additional features to pcb or to products? (like cables/power supply/rtc battery for vim,…)

About PCBA I would like make a full set first, later I can imagine to try prepare a cheaper variants without some features, about changes in PCB is always possible

  • when is makes sense,
  • will suits better,
  • can be fit and not explode a price.

So kind of Wish list it’s possible after while when we/I’m see, that needs to be something optimize. I’m very open minded. Some thoughts around, the components are only from top due to better prices for PCB assembly. There isn’t so many places for newest designs, but maybe something really important we should add. I would like brings first designs in the field and let’s figure out how is works for you and me.

Only concerns I have, how much will be changed new VIM, hmm? Q2 is ending, maybe some new info’s/updates will be appreciated (announced is new SoC, but what else…)


I mean the creation of new(other) card with a different set of elements. For example I want to charge with a set of USB ports with extra food (the line for data transmission can be connected, through the contacts for USB to 40-pin expansion port VIM), and the power add USB to take expansion boards. Ports for microphone and output for speakers\headphones connector SPDIF / coax. With the power connector on the additional Board (mini USB and DC 2/1) and rtc battery. To connect additional fee to VIM, can use a flexible ribbon cable (similar to that which was previously connected IDE HDD or floppy disks). Power to VIM feeding through the connector with the VIP expansion Board. Then this extra cost can be placed from the bottom under the main Board and leave the possibility to use additional fan on staff housing at the top.

I’m definitively interested and will get one of those if they get produced.

Coooool! PIN Globally for 8 days!

Hi, Tomas:
Khadas Team will provide more support including business support if needed, for example:

  • We can provide our distributors like Gearbest to sale your board.
  • We will provide the VIM2 GPIO Mapout ahead to you, to make sure your board will support VIM2 device.
  • Further support if you needed

Just let us know if you need support!

Hi, Tomas:
Do you agree that a GPIO controllable cooling fan will be better? Some users feedback to us that the cooling fan is a little bit noise if the fan keep running always.

BTW, a header/slot to support Khadas official cooling fan will also be meaningful for us:

  • 2-Pin 1.25mm Pinch header
  • 2-Pin 1.00mm Pinch header (For VIM2 and newer Khadas products, VIM2 will built-in the cooling fan slot)

Congratulations on your work, i will wait until the first prototypes become available, when i see this in action, but at first this is amazing, i thought khadas team will develop something like this.

Why don’t you make one more board like balbes150 said, maybe a few prototypes, his suggestions are also great, if it will be compatible with Vim and Vim2, i am sure you can earn some money, if you don’t get enough interest, do not sell it.

As you can see, Vim team will help you to sell the board, this really adds functionality to Vim, i was hoping for something like this, but i didn’t expect this to come from the user, great job!!!

1 Like

Hello Gouwa,

thanks for feedback, appreciated, I will for sure contact you to figure out if/how is GPIO Changed… And happy from support.

You are right, it’s better options, so I’m try surprise myself and I try put circuit into board for controlling FAN by GPIO. And I have Answer, it can be :smiley: Schematic and placement is up-to-date now.

I’m find a place for circuit for PWM_F GPIO Controlled FAN. By default looks that GPIO pin is floating, so 10k Pullup will activated FAN permanently (when PWR_EN is active, of course) and by SW can be turn off. If PWM_F can be really somehow support PWM, rpm speed of fan can be controlled by gpio. But at least on/off functions based on running SW can be achievable.

I’m fix a connectors, now is support for 1.0mm and 1.25mm fan (just needs clarified with supplier a both connectors). See modified silkscreen.


this is a brilliant idea

I encourage you to go further.
Please give me a detailed pdf to my mail id given below.

Hello TomasFilip,

what’s the current state of your project? Is there any progess? I’m also interested in your board.
It’s a very good idea, because of the lack of an extra audio output on VIM/VIM2 and the other
features improves the system…

Thanks and best regards - Andy

I’m definitively interested and will get one of those if they get produced. * We can provide our distributors like Gearbest to sale your board.

  • We will provide the VIM2 GPIO Mapout ahead to you, here is support servive provider Acer Support Number to make sure your board will support VIM2 device.
  • Further support if you needed

I am really happy to found this important post,If you have any query then you can free to visit Holi wishes blog.

Also interested in this especially if it would be compatible with VIM2. This would allow me to use the Tone board with SPDIF in from the VIM2 and usb in from my computer. I believe that usb has priority on the Tone board which would be ideal.

Hi Tomas, I am really interested in your project, and I am sure that I will not able to make it by myself.
Could you make one for me? And sell it? I did just purchased the new VIM3L
Thank you