Forum - Recent Threads

RE: CT3679 Twin Lead Adapter, Probe Compatibility

baldengineer — Thu, 01 Jun 2023 04:01:52 GMT

adds item to todo list ...

CT3679 Twin Lead Adapter, Probe Compatibility

baldengineer — Wed, 31 May 2023 15:35:04 GMT

The CT3679 Twin Lead adapter converts a 5 mm oscilloscope probe to a two-socket connection. You can either connect those sockets to header pins or use the included SMD grabbers to connect to small leads. While they obviously work well with Cal Test's own probes, they may also work with other 5 mm scope probes. But, as you can see in this Workbench Wednesdays Video, not all of them!

Compatible Probes

Multicomp Pro OW3200
Rigol RP2200

Not Compatible Probes

Rigol P6060
R&S RT-ZI10C Isolated Passive Probe
YPioneer P4100 100X High Voltage Probe

Obviously, this is not a comprehensive list. These are just the 5mm probes I have in my lab. Post your experience with the CT3679 below.

Purchasing

I recommend having at least one of Cal Test's probes since they fit well together. I recommend the CT3133RA. It's a 350 MHz probe. My testing shows you really only get about 90-100 MHz out of the adapters before they start ringing.

Remember, the "RA" at the end means the probe has the pin to indicate to the oscilloscope it is a 10-to-1 probe.

The CT3679 Twin Lead adapter is also available in the [embed:ad4490ac-0ce8-4f2d-a04c-9285646d5689:74fbe3ee-e8db-46cd-8c25-605154a3a123:text=CT3288ARA&style=link&farnell=2850344&newark=50AC8915&cpc=&avnetemea=&avnetema=&avnetasia=&comoverride=&cmpoverride=&AreaInteracted=rte-content&bom=] kit.

Its part number ends in "ARA."
The first A means it includes additional accessories like the twin lead adapter.

Video

If you haven't watched it yet, there's a full video on the twin lead adapter, watch it here.

RE: CT3679 Twin Lead Adapter, Probe Compatibility

shabaz — Wed, 31 May 2023 16:07:38 GMT

Interesting item!

I had a similar need for the R&S probes, and by chance noticed that they fit 2.5mm audio sockets. It's not a brilliant solution (and for sure there's a risk of tip breakage, but I've not noticed any sideways bending of the tip so far). The official kit for the probes is more than I wanted to pay for now. I might try to come up with a better solution at some point, but may just adapt the DIY solderable probes to a version with pin sockets (again non-ideal compared to the proper kit!).

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

colporteur — Fri, 31 Mar 2023 21:07:33 GMT

If he is taking orders, I'm willing to put my money with my mouth. Thanks just the same for looking into it.

Microcontroller Dev Boards: What features do you like to have (or to add?)

baldengineer — Sun, 15 Jan 2023 15:56:39 GMT

A couple of weeks ago, I bribed [mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05] (with coffee) to send me one of his Pi PIco Eurocards. As the name implies, these are a development board for the Pi Pico / RP2040. In the past, another friend sent me one of his all-in-one microcontroller development boards (pictured above). And I have designed a few boards that had development features on them. Besides those, boards like Adafruit's Feathers or even the iconic Arduino Uno could be considered dev boards. Last, historically, microcontroller manufacturers had elaborate evaluation platforms for their chips.

All of these points made me wonder: what are the features YOU want to see in a microcontroller development board?

If we use [mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05]'s Eurocard, some notable features are:

Headers for changing power source (external / Pi Pico / Programmer)
Integrated programmer/debugger (RP2040-based Xiao, in this case)
Prototype areas for through-hole and surface mount parts
SD Card
Button
LED
(and many more)

In addition to features, what tricks or tips have people learned when making a board like this one?

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

baldengineer — Fri, 31 Mar 2023 18:23:29 GMT

The creator is a friend of mine. He started working on a Rev 3 a while back. During the parts shortage, he could not get parts for the redesigned power supply. So it went on the back burner.

To be upfront, I used the image here to poke him about the project. But it seems unlikely he'll come back to it any time soon.

So, no updates, sadly.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

colporteur — Fri, 31 Mar 2023 16:14:30 GMT

BE, the Practical IOT Microcontroller Trainer Rev 2.0 has been retired (https://www.tindie.com/products/bluesmokemonster/practical-iot-microcontroller-trainer-rev-20/ ). Do you have any updates on the product?

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

Workshopshed — Fri, 31 Mar 2023 05:39:32 GMT

For me the biggest issue with some of the dev boards I've played with are the "gotchas".

Such as pins labelled as TX and RX but then are not actually usable as serial as they are wired to something else such as a WiFi module. Or something as simple as a pull-up or LED meaning you can't use a particular pin in the way you intend.

Or where the underlying processor supports multiple PWM but the board can't because of the eco system not supporting it.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

CargoCultScientist — Wed, 29 Mar 2023 00:20:22 GMT

It's great to see how the community comes together to create and share different microcontroller development boards! Here are some features that I think many users would like to see in a microcontroller development board:

Breadboard compatibility: A development board that is breadboard-friendly makes it easier for users to prototype and test their circuits quickly.
Multiple power options: Having the flexibility to power the board through USB, an external power supply, or a battery can be beneficial for various projects.
Built-in debugger/programmer: A built-in debugger/programmer can simplify the development process and eliminate the need for external tools.
Comprehensive documentation and support: Detailed documentation, examples, and tutorials can help users get started and make the most of the development board's features.
Wide range of GPIO pins: A development board with a sufficient number of GPIO pins, including digital, analog, and PWM pins, provides flexibility for different project requirements.
Connectivity options: Built-in support for communication protocols such as I2C, SPI, UART, and USB, along with wireless options like Wi-Fi, Bluetooth, and LoRa, can enhance the versatility of the development board.
Expandability: A development board with expansion headers or slots for additional modules, shields, or HATs allows users to add more functionalities to their projects as needed.
Onboard sensors and peripherals: Including basic sensors (temperature, humidity, accelerometer) and peripherals (LEDs, buttons, displays) on the development board can enable users to experiment with various components without the need for external modules.
Robust voltage regulation and protection: A development board with efficient voltage regulation and protection circuits ensures stable operation and safeguards the board from potential damage.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

shabaz — Mon, 16 Jan 2023 21:28:41 GMT

I felt the same : ) On the revision 2 board that is in the photo above, the text still feels small, so on the more recent rev 2.2 board the text labels for each pin are bigger where possible.

Actually, that's another desirable requirement for dev-boards, to have the text all oriented one direction (i.e. not having to read text sideways). This is not always practical though.

The rev 2.2 also has a few minor changes, such as locating all the surface-mount parts, including the micro SD connector, on the underside, to be easier to assemble):

Wish there was an option for glow-in-the-dark silkscreen : ) Or there could be lit dev-boards with small LEDs illuminating it to be able to always read the text clearly. One simple way to do that : ) could be a wood box/tray around dev-boards, with LED strips pointing inward : ) I'm surprised Arduino etc do not offer that! : )

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

dougw — Mon, 16 Jan 2023 16:50:37 GMT

Stacking connectors are also very useful on some dev cards.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

baldengineer — Mon, 16 Jan 2023 16:33:34 GMT

[quote userid="41967" url="~/challenges-projects/element14-presents/workbenchwednesdays/f/forum/52324/microcontroller-dev-boards-what-features-do-you-like-to-have-or-to-add/205004"]Shabaz' board looks more like a dev board that might be used primarily for developing a single project prior to a first PCB design[/quote]

I agree the definitions are vague. (Admittedly, I did not define "development board" on purpose.)

That said, the two boards, in my opinion, are extremely similar. The biggest difference is that the top board supports multiple microcontrollers, while Shabaz's only supports the Pi Pico. Both accept microcontrollers, support flexible power supplies, and have a handful of useful peripherals across multiple projects.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

shabaz — Sun, 15 Jan 2023 23:53:01 GMT

It had really nice machine code (very good for the C compiler!) and had UART bootloader. Meanwhile, even the much later (by a decade or more) PIC microcontrollers were completely missing that, requiring a relatively expensive programmer (about $150-$200 from memory).

I couldn't afford expensive programmers, so tended to use nice chips like the 68HC11 series, and also the Hitachi H8 series (they had UART bootloader too, and rich instruction set).

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

shabaz — Sun, 15 Jan 2023 23:17:39 GMT

Another benefit of large boards is that they can house a lot of project : ) That trainer board's breadboard area could be used to carry a PCB or stripboard or perfboard etc, just placed or pushed on top. I do the same thing on the Pico board.

I was experimenting with audio in the photo here. Since this amplifier board needed 12V, I could take that power from the screw terminals visible at the right side of the photo, powering everything from the single barrel connector.

I don't use many MikroE Click boards, but I needed one here, so I prototyped a Click adapter to plug on top. Actually normal stripboard/perfboard can be plugged on, but I had a few older revision Pico Eurocard boards so I cut one in half to plug on top here. Might as well reuse scrap boards if possible:

GPIO pins in order can help sometimes; the connector on the right side is organized in that order, so the LED 7-segments could be nicely in A-G segment sequence on the header:

Soldered parts on the main area:

The parts are really easy to desolder (so that the board can be reused many times) because of this; there's a gap between the holes and the pads:

Incidentally, 30 AWG wire is always handy to have on hand for creating projects/fixing circuit board problems etc.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

misaz — Sun, 15 Jan 2023 21:05:06 GMT

I disntiguish three types of board usualy refered as:

Breakout/prototyping boards. Examples: Raspberry Pi Pico, STM32 Blue Pill
Development Kit. Examples: STM32 Nucleo, STM32 Discovery, Renesas EK-RA, Cypress PSoC Pioneer boards, SIlicon Labs Explorer Kits, Microchip Curiosity Nano, Maxim FTHR boards, Nordic nRF52, nRF53 and nRF91 devkits
Evaluation Kit: STM32 Evaluation Kits

The first is simple. No necessary connectors, components and so on. Usualy they have exposed all or almost all pins. They are good for low-power applications because except MCU there is nothing else consuming energy.

Difference between second and thinrd is in the scope of offered feature. The last should allow user to evaluate ALL features of the MCU while the middle option allows using (smartly selected) subset of the feature. Most devkits are in second group. I guess it is because second group offer best price/performance ratio. First category is good for low-pin MCUs but for higher count MCU it became annoying. Second category offsers good onboard peripherals and allows use most of features without heavy external circuits. Third option is used for users who have needs for heavily using the MCU and need to develop firmware before make prototypes of their own huge boards. Third category is the most expensive, but this boards often contains tons of connectors, sensors, large displays, several connectivity options,... In other words evaluation board (like this one) contains everything but are expensive.

Nowadays almost every board (currently also including many board classified to first category) has onboard JTAG/SWD debugger and we do not need buying expensive external debugger anymore. It is extremely usefull benefit in comparison with boards avalaible 15 years ago.

My most favourite development kit design is Renesas EK-RA like EK-RA2L1 which I reviewed as part of roadtest: Review of Renesas EK-RA2L1 Development Board

It has very few onboard peripherals, but has lot of connectors for most commonly used interfaces: Arduino Uno compatible connector, MIkroE socket, Qwiic, Grove, PMOD. Except these connectors all pins are accessible on dedicated connectors. It is very usefull for connecting logic analyzer. I like this design very much. Other very good options is that all devekits in this serie share the same design, so if you ware familiar wiht one kit, you can freelky move to the other one. They are expensive, but Renesas offers free samples 🙂

Second boards which I frequently use are STM Discovery and Nucleo boards. Nucleo shares the samilar design pattern as Renesas EK-RA. In case of STM I like discovery boards over Nucleos because disco boards add some interesting peripherals.

Nowadays many vendors try to standardize even their breakoutable/prototyping boards. For example recently I played with Silicon Labs EFR32BG22. Silicon labs makes their explorer kits which all have the same (small) form factor, onboard debugger, MikroE socket and exposes all other pins. They use this form factor for all their MCUs no matter if they support BLE or not, are 8-bit or 32-bit and so on.

At last I like boards which has something very unique and advanced but vendor designed to offer them at very competitive price for promoting their products. For example MAX78000FTHR. I basicaly described it in my blog Received Project14 7-segment Display Competition Reward . It is 30 USD board with advanced dual core MCU with AI accelerator, on-board debugger, camera, audio codec (+ jacks), other MEMS microphone and allows running from battery (has on-board li-pol/li-ion charger). Very few boards are so tiny, so performant, so cheap and allows so much interesting use cases. But it has other disadvantage like hard firmware development.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

dang74 — Sun, 15 Jan 2023 18:50:58 GMT

I like simplicity. As they say less is more. Important criteria for me is:

1. Easy method to configure

2. Easy method to power

3. Sufficient I/O made accessible (as others have mentioned)

4. If the board can act as a module and be mounted on a custom board to add extra functionality that is great too.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

beacon_dave — Sun, 15 Jan 2023 18:30:01 GMT

Perhaps may need to differentiate between different classes of board definition here, although with access to cheap one-off PCB manufacture these days, and entire systems on a single chip, then the lines may have now blurred a bit.

The first board looks more like a trainer or prototyping class board as it has additional IO devices included on the board and looks like it may be used many times for different tutorial type projects. The breadboard suggests that it may be used for many different hardware designs throughout its life.

Shabaz' board looks more like a dev board that might be used primarily for developing a single project prior to a first PCB design. It looks like it could be populated with additional components and be slotted into a rack enclosure for prolonged testing. It has options for additional debugging type modules but doesn't have much in the way of on-board IO devices.

Historically that first one-off PCB would have been an expensive step, and it was likely cheaper to get a mass-produced 'dev board' that basically provided you with the device plus supporting hardware with its pins broken out to easy to work with connections.

Then there is the likes of the evaluation board which may have minimal core components plus a specific sensor or actuator intended to allow you more quickly test the functionality of a specific device.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

michaelkellett — Sun, 15 Jan 2023 18:12:26 GMT

Keep it simple.

Power supply input, on board regulator and clock.

Break out every pin.

Serial port, debug programming port.

0.1" headers are good and cheap but sometimesd take up too much room.

Some mounting holes so the board can be fixed to box or other boards.

I've been using my little display board as a general purpose micro board recently (where others might use a Pico or an Arduino).

The display board is the one in the vice. It doesn't have much more than the absolute basics (it has power siwtches for the displays and a possible back light.) The serial interface doesn't use an RS232 drive chip but works at logic level.

The thing it's connected to is a multiplexer and DC bias injector for an LCR meter. (I'll blog about it when it's working a bit more.)

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

dougw — Sun, 15 Jan 2023 18:05:58 GMT

The 68HC11 was an awesome chip at the time.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

shabaz — Sun, 15 Jan 2023 16:56:25 GMT

I'm also finding the built-in supplies really handy. I like working on laptop on sofa or wherever, and it means I can just use any DC power supply, and have access to 5V or 3.3V rails for circuitry. I'm using the supply feature a lot (although the Pico is unusual in that it is fairly generous with what it can supply).

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

scottiebabe — Sun, 15 Jan 2023 16:46:25 GMT

A silkscreen that is easy to read.. (on both sides)

Ohh and ❤ Micropython support ❤

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

shabaz — Sun, 15 Jan 2023 16:44:45 GMT

At uni I used this microcontroller dev-board quite a few times:

(Image source: Google Images)

the play area on the right was really handy for making projects. There wasn't really much else that the board did. It had built-in RS232 for programming or comms. It had an option for adding a real-time clock. I really liked it so after I left uni I made my own version of this (on proto-board with tons of wiring,no PCB) but with the microcontroller replaced with a version that could have external memory (I think I used parallel EEPROM). That helped loads, since otherwise you had to run code from RAM (which was limited to 512 bytes), or use one-time programmable ROM, or EPROM window versions.

I learned these suggestions that suited me, but might not suit everyone, when working on the Pico Eurocard:

1. Keep it simple
2. At least two connections per pin, using pin headers or whatever your favorite connectors, makes it easy to simultaneously probe. Try to make it easy to access buses like I2C, SPI.
3. Examine the chip datasheet, and see which pins are are least likely to be needed for SPI/I2C etc, and use them for some sort of minimal I/O like buttons and LEDs, but use jumpers to disable or re-patch them to other I/O if needed
4. If there is no USB serial debug capability on the microcontroller, then strongly consider adding at least the UART connections onto a pin header, laid out to fit your favorite USB-UART adapter, or better yet, solder one permanently on, since it helps troubleshooting immensely if you can use print statements in your code. I also like creating a keypress entry menu, so that code can be tested without requiring buttons/displays
5. Use the ARM SWD or JTAG connections (or whatever the microcontroller supports) because it can often be much quicker. This is easy with the Pico becase the debugger happens to be another RP2040 in that XIAO module of course.
6. You can't please everyone, everyone will have their preferred displays and connectors and so on, so consider the board as a kind of test card for the processor, and just have plenty of connections for easy extension. In other words, keep it simple.
7. If you're creating a prototyping area, then if you deliberately don't make the pads through-hole, then components are extremely easy to desolder, since the copper won't quite reach the drilled holes, it will automatically be set back a bit, with all low-cost prototyping services.
8. If you use an ecosystem a lot, like MikroBus, then you could either add the footprint, or alternatively make yourself a carrier card/plug on board for it.
9. Since it's a dev-board/test card, it doesn't need to be ultra-compact. Consider 100x100 mm as a starting point, since that is often a low cost from the PCB services.
10. Since the user will often need access to connections, it often rules out a plastic enclosure, but instead consider either mounting feet, or use screw-holes to attach a plastic plate on the underside and top. The latter is usually an excellent idea, since you don't want a stray wire on your desk to touch something.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

wolfgangfriedrich — Sun, 15 Jan 2023 16:43:13 GMT

I just want to point out one feature, which is really nicely done on both of those boards. The markings of connectors and everything else in silkscreen. Pin numbers or signal labels in readable size, also the grid on the prototyping area.

TLDR: If there is room, add more text.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

dougw — Sun, 15 Jan 2023 16:40:45 GMT

I think of it as 4 levels of dev card, each is useful:

The starting point as Jan Cumps would say is to breakout every pin of the MCU onto a header and provide enough infrastructure to program and rum.
The next step up for me would be to incorporate standard connectors for standard interfaces. Like USB, UART, SPI + power, I2C + power, Analog + power, digital + power, servo, etc.
The next step up for me would be to incorporate standard connectors for standard peripherals and communication functions. Like a display or HDMI, keypad, Bluetooth, WiFi, audio, video, MIPI, SD, etc.
Then finally more complete but constrained systems that include on-board peripherals like displays, sensors, speakers, keypads, cameras, microphones, etc.

The difference between level 2 and 3 is that level 2 is mostly adding purpose connectors for MCU functions, where level 3 generally needs support chips or areas for peripherals to reside.

There might only be 1 type of level 1 module, but as the levels get more complex, the number of variants would increase to accommodate different feature sets.

I'm not a big fan of breadboard areas on a dev card since it wastes space and I generally use custom PCBs to perform "breadboard" functions.

If modules try to make a one-size-fits-all solution it ends up to have a lot of wasted resources or it is too costly or it consumes too much power or it is too big.

RE: Microcontroller Dev Boards: What features do you like to have (or to add?)

mayermakes — Sun, 15 Jan 2023 16:03:34 GMT

i don't really have requests in stuff that should be on the board, I prefer to have zero clutter or parts that I don't really use in the project present to avoid conflicts and confusion on my part. also I don´t like any customization in routing that require Arduino cores, DTOs or any other compability layer , not even a renumbering of the pins. Everything should work exactly as if I put the bare chip I build upon on a board, NO deviationsm no porting.
My biggest request is to have Flawless software support OOTB, no special linux derivates that never get updated or proprietary SDKs.
a simple way without any additonal hardware to flash code / boot (native usb for example is great)
and absolutelly Open source construction, no proprietary software needed and only Bog standard mainline Linux support on day one. that would be my biggest request.