Is it possible to set the lowest voltage allowed to output at 12 or 20 volts? In other terms, stop it from outputting 5v(Output 12v or 20v only). Using the USB-c trigger ZYPDS from here (https://www.aliexpress.com/item/32969919810.html). Other people will be using a project im working on that uses this usb-c trigger to supply 12 volt to an LED driver. If they accidentally use a standard (Type A) USB to USB-c wall adapter, it will damage the LED driver im using which cannot operate at 5v. Any Suggestions? The part number on the chip being used on the USB-c trigger is ip2721. I cannot read chines but here is the datasheet (http://www.szjuquan.com/upload_files/qb_sell_/pdf/IP2721.pdf).
I would suggest using a Zener diode. Ignore all those voltage regulator tutorials, since that's not how you would be using it. Instead by simply whacking it in series, without a resistor, you are using it as a gate. I would almost consider using a 9v Zener in this application, provided the chip never outputs 9v.
Leave it floating.
I've just "read" the Chinese manual, the settings are:
* pull down: 5V
* pull up: 20V
* floating: 15V
BTW From my experience the chip isn't very stable.
Related
This is probably a long shot question, but I try it anyway.
I'm developing hardware using PIC Microcontrollers (MicroChip). Communication is done through a FS USB 2.0 link.
I connect the microcontrollers to a Windows 10 Home edition, version 21H1, build 19043.1826. The processor is an AMD Ryzen 5 3600 6-Core Processor.
First I used the PIC18F45K50, for which everything worked fine from day one. But due to the shortages on the market, I now am experimenting with PIC18F47J53. Both microcontrollers are working fine, as I can (for example) control a MAX7219 controlled display (3 x 7-segment) and also control a bunch of LED's using an STP08CP05TTR. Clock timings seem also ok - I measured it with an oscilloscope.
These 2 microcontrollers are pretty much the same, at least for the core functionality such as USB. The differences that are relevant for the issue I'm reporting here are:
PIC18F45K50 uses internal clock of 8MHz, and has on board correction logic to keep clock synced for HS USB - this is a 5V processor
PIC18F47J53 uses a XTAL of 16MHz, all should be within the USB 2.0 specs - this is a 3.3V processor
I'm using the MPLab X IDE v5.45 with the MCC (MPLab Code Configurator) in which I setup the System Module (to set the correct clock frequencies including the 48MHz for USB) and where I configure the USB.
In both microcontrollers, the setup of the USB is exactly the same. I even checked the 4 files that are automatically generated by MCC, and except for the descriptors (I used different names), all is exactly the same.
When I connect the USB to my PC (same port), then the PIC18F45K50 works perfect. But the PIC18F47J53 gives error code 10.
This does not happen every time. For example, if I try 10 times (connect/disconnect the cable), then I had it 7 times. 1 time the device even didn't appear, and 2 other times I read "The device is working properly.". Although, in the latter case, my software that communicates with my controller isn't working, so there is still something wrong.
Based on the above, the first I would think of is some hardware issue. Although, the strange thing is that things like vendor ID (0x4D8), Product ID (0xA), BCD Device Release (0x100), Serial Number (12345678), etc... seem always to be read out correctly. If there would be a hardware problem, shouldn't I have more random issues with this as well? Or is this data read out in a slower mode than Full Speed (because that could of course explain this)?
Below are screenshots via "Device Manager / Ports (COM & LPT) / my serial device", then selecting the property in the Details.
If I compare the properties from the working microcontroller (PIC18F45K50) with the not working one (PIC18F47J53), it looks like all are exactly the same.
I also tried to compare the D- (CH1) and D+ (CH2) signals between the 2 microcontrollers with my oscilloscope. My USB knowledge is not detailed enough to interpret the signals, but what I can tell is that both look exactly the same to me, both timing wise and voltage level wise. Be aware that the CH2 signal on the PIC18F47J53 (D+), the second screenshot, is clipping in the picture below, but I measured it later and it shows the same voltage level as for the PIC18F45K50.
Does anybody here a single clue where I should look at in the first place? The good news is that I have a working and not working version, so I can start debugging step by step and compare. But some hints as where to start would be appreciated.
EDIT 24JUL2022
I did the measurement with my oscilloscope again. Now I soldered 2 wires to the USB port to be able to easily attach my probes. This time, both D- and D+ signals have a Vpp of about 3.3V. I put some cursors which also shows a pulse-width of about 84ns, which correlates with the USB HS frequency of 12MHz (should be 83.33ns).
I found the issue. The Vusb on my PIC18F47J53 had a bad (or was even not) connected. I gave it another touch of my soldering iron, and bingo! Now the "error 10" has disappeared completely, and each time I connect/disconnect it gives "This device is working properly.", and error 10 never appears. I now also see a continues signal on my oscilloscope - not one that is disappearing after a while. And I could send/receive already some commands.
I'm trying to connect to stm32f401rbt6 with st-link utility.
The MCU has 6 pins connected, as on the image below.
The target is powered by a lab power supply, target GND is connected to the ST-Link GND
When I plug it to the computer, st-link utility says it can't connect.
Tried:
Update ST-Link firmware
Connect under reset is by default, tried all available methods
Checked connectivity for the pins on the image
Connected with the same ST-Link to other MCU
Desoldered the MCU and soldered another one
The issue is still remain. Please suggest what I'm doing wrong, or how to check that my MCU is alive.
I once had similiar issues and i figuered out, that decoupling capacitors were vital. After soldering this onto the pcb, it worked like a charm.
(Similar question: Stm32CubeProgrammer not connecting (no error msg) using ST-LINK V2 dongle and Lora E5 mini board)
You can try the following suggestions. Some ST devices are a lot more sensitive than others when it comes to programming. I have had some ST devices programming without issues and then using practically the same setup on other devices it just won't work.
Place a 22ohm resistor in series on the SWDIO and SWCLK lines. This link suggests only placing it on the SWDIO line but I found that I needed it on the SWCLK line as well. Typical SWD Circuit
For the ST Link Settings try using these:
Reduce the frequency from 4MHz to a lower frequency
Use SWD
Use connect under reset
Don't use an external pull-up on the NRST line.
Make sure that your programming wires between the ST-LINK and the target board are as short as is conveniently possible.
(This one I must stress as being important) Make sure that your processor's ground pins are all connected very closely together (i.e. the tracks between them are as short as possible) and that very importantly your programmer ground is also connected to the same ground pins very closely.- At high programming speeds a thin or long unbalanced (different length) ground track to the processor can cause a problem with some devices.
Whatever you are using to supply power to the processor must have a supply with a similar voltage as the ST-LINK (mine is 3V) - (although I have found that if the processor supply is 3.3V programming seems to still work most of the time.) (Remember the original ST-Link does not supply power only reads the power level.)
A dodgy programming setup can accidentally set the protection to LEVEL 2 bricking your device - so if you have been trying and not getting any further, it might be time to replace your IC.
Prior to changing / erasing a device that had been programmed to LEVEL 1, you might need to first enable the PCROP_RDP option byte. - Once enabled, you should be able to change from LEVEL 1 to LEVEL 0 that will automatically erase the device.
Some people have suggested holding the device in reset until just after pressing the erase button to enable erasing it.
I hope these suggestions help...
OK, so I have a 3 pin 315/433MHz rf reader module which I've connected to my raspberry pi 2. 2 pins are for Voltage and ground, and 3rd goes to a GPIO pin configured as input.
I've actually gotten all of this to work just fine. I can read data manually from the GPIO pin just fine, by accessing the file
/sys/class/gpio/gpio23/value
I can even place a car key next to the receiver press a button, and see the values change between 0 and 1.
The problem is that I cannot figure out how to read the clock, so I cannot figure out if there are supposed to be multiple ones or zeros in a row in the data its reading. There doesn't seem to be any time stamp that I can find to see when the last value was read.
How can I properly read the data the module is receiving?
There are two common protocols used for 315/434 MHz radio transmission by hobbyists (that I know of).
Keyfob type remote control devices tend to use Manchester Encoding.
General data transmission using the Virtual Wire protocol (as popular with Arduinos).
My pigpio library has a Python Virtual Wire implementation and C/Python keyfob Manchester Encoding example (for receive and transmit).
your RF reader should be outputting serial data at some known baud rate (check the manual?) assuming you haven't wired it up to the dedicated serial pins you could look at using the pigpio library, more specifically the bit banging serial commands here for python or here for C/C++ or here for pipes
This allows you to use any GPIO pin for reading serial data and the library has bindings for several methods of use as shown in the links above.
Hi Im using the following RF module
http://www.apogeekits.com/rf_receiver_module_rx433.htm
on an embedded board with the PIC16F628A. Sadly, I realized that the signal strength was in analog form and couldn't get any ideas to get the RSSI reading off the pin because well my PIC is digital DUH!.
My basic idea was
To get the RSSI value from my Receiver
Send it to the PIC
Link the PIC to a PC via RS232
Plot a graph of time vs RSSI of the receiver (so I can make out how close my TX is to my RX)
I thought it was bloody brilliant at first but ive hit a dead end here. Any ideas on getting the RSSI data to my PC from this receiver would be nice.
Thanks in Advance
You can get a PIC that has an integrated ADC for sampling the analog signal. Or, you can use an external ADC chip to do the conversion. You would connect that to your PIC using SPI or I2C.
The simplest thing to do is obviously to use a more appropriate microcontroller - one with an ADC! There are many (most), including PICs (though that wouldn't be my first choice).
Attaching an external SPI or I2C ADC might be a bit tedious since having no SPI or I2C on your part, you'd have to bit-bash it. If you do that, use an SPI part - its simpler. Your sample rate will suffer and may end-up being a bit jittery if you are not careful.
Another solution is to use a voltage controlled PWM, then use the timer input capture to time the pulse width. That will give you good regularity and potentially good resolution. You can get a chip (example) to do that, or grow your own. That last option requires a triangle wave input as well as the measured (control) voltage, but on the same site...
In a similar vein, you could use a low frequency VCO (example) and use the output to clock one of the timers, then using a second timer periodically sampling the first and reset it. The count will relate to the voltage, though not necessarily a linear relationship, linearisation could be none on the PIC or at the receiving PC - I'd go for the latter - your micro will suck at arithmetic (performance wise) - even integer arithmetic, especially if it involves division.
I'd like to start out with the Arduino to make something that will (preferably) dim my room lights and turn on some recessed lighting for my computer when a button or switch is activated.
First of all, is this even possible with the Arduino?
Secondly, how would I switch on and off real lights with it? Some sort of relay, maybe?
Does anyone know of a good tutorial or something where at least parts of this are covered? I'll have no problems with the programming, just don't know where to start with hardware.
An alternative (and safer than playing with triacs – trust me I've been shocked by one once and that's enough!) is to use X-10 home automation devices.
There is a PC (RS232) device (CM12U UK or CM11 US) you can get to control the others. You can also get lamp modules that fit between your lamp and the wall outlet which allows you to dim the lamp by sending signals over the mains and switch modules which switch loads on and off.
The Arduino has a TTL level RS232 connector (it's basically what the USB connection uses) – Pins 0 and 1 on the Diecimila so you could use that, connect it via a level converter which you can buy or make and connect to the X-10 controller, theirs instructions on the on the Arduino website for making a RS232 port.
Alternatively you could use something like the FireCracker for X-10 which uses 310MHz (US) or 433MHz (UK) and have your Arduino send out RF signals which the TM12U converts into proper X-10 mains signals for the dimmers etc.
In the US the X-10 modules are really cheep as well (sadly not the case in the UK).
Most people do it using triacs. A triac is like two diodes in anti-parallel (in parallel, but with their polarity reversed) with a trigger pin. A triac conducts current in either direction only when it's triggered. Once triggered, it acts as a regular diode, it continues to conduct until the current drops bellow its threshold.
You can see it as a bi-directional switch on a AC line and can vary the mean current by triggering it in different moments relative to the moment the AC sine-wave crosses zero.
Roughly, it works like this: At the AC sine-wave zero, your diodes turn off and your lamp doesn't get any power. If you trigger the diodes, say, halfway through the sine's swing, you lamp will get half the normal current it would get, so it lights with half of it's power, until the sine-wave crosses zero again. At this point you start over.
If you trigger the triac sooner, your lamp will get current for a longer time interval, glowing brighter. If you trigger your triac latter, your lamp glows fainter.
The same applies to any AC load.
It is almost the same principle of PWM for DC. You turn your current source on and off quicker than your load can react, The amount of time it is turned on is proportional to the current your load will receive.
How do you do that with your arduino?
In simple terms you must first find the zero-crossing of the mains, then you set up a timer/delay and at its end you trigger the triac.
To detect the zero-crossing one normally uses an optocoupler. You connect the led side of the coupler with the mains and the transistor side with the interrupt pin of your arduino.
You can connect your arduino IO pins directly to the triacs' triggers, bu I would use another optocoupler just to be on the safe side.
When the sine-wave approaches zero, you get a pulse on your interrupt pin.
At this interrupt you set up a timer. the longer the timer, the less power your load will get. You also reset your triacs' pins state.
At this timers' interrupt you set your IO pins to trigger the triacs.
Of course you must understand a little about the hardware side so you don't fry your board, and burn your house,
And it goes without saying you must be careful not to kill yourself when dealing with mains AC =).
HERE is the project that got me started some time ago.
It uses AVRs so it should be easy to adapt to an arduino.
It is also quite complete, with schematics.
Their software is a bit on the complex side, so you should start with something simpler.
There is just a ton of this kind of stuff at the Make magazine site. I think you can even find some examples of similar hacks.
I use MOSFET for dimming 12V LED strips using Arduino. I chose IRF3710 for my project with a heat sink to be sure, and it works fine. I tested with 12V halogen lamp, it worked too.
I connect PWM output pin from Arduino directly to mosfet's gate pin, and use analogWrite in code to control brightness.
Regarding 2nd question about controlling lights, you can switch on/off 220V using relays, as partially seen on my photo, there are many boards for this, I chose this:
As a quick-start, you can get yourself one of those dimmerpacks (50-80€ for four lamps).
then build the electronics for the arduino to send DMX controls:
Arduino DMX shield
You'll get yourself both the arduino-expirience + a good chance of not frying your surrounding with higher voltage..