Hi Gef
Those expansion devices over I2C will not be much good at all for analog signals. They are really suitable for low speed digital IO. There are SPI versions of these devices available that can obviously increase the update bandwidth...
This seems very curious and not the norm:
Typically the SPI bus is shared and additional CS lines are used to select the chip you want to talk to. Why are they doing it this way?
bigDlin do you have them wired this way? Is it working?
Also I...
Is the data actually 32bits? or is it a 24bit converter sending a 4byte result?
Depending on the converter, some will allow the result (eg ADC) to be sent as 3 bytes (24bits) instead of the 32 saying you 25% throughput.
I had been using PCBWay for everything up until recently when they dramatically increased their pricing on 4 layer boards.
A 100mm x 100mm 4 layer board from PCB Way is about 4 to 5 times the price of the same design from JLCPCB which I found...
SdFat is blocking for both read and write. There is a fairly recent thread where someone modified SdFat to do non-blocking reads, but not writes. There is a way, though, to limit blocking times to 5-6 us and avoid the very long blocking times of...
Hi DrM
My ADC input full range is only +-1.2V hence the +-4V is plenty of room.
I am using these as my front end buffer amplifiers. They are working very well in my current application...
yeah that would be nice as well. Honestly anything at this point would be a game changer. I'm currently developing a fairly large program for a teensy 4.1 with freeRTOS and the software debugger (https://github.com/ftrias/TeensyDebug) just...
Hi DrM
Looking good. How much current and at what voltage ripple are you getting out of your design?
I have now used a charge pump device to do something similar but with 5V input and +-4V outputs. I have a DAQ board which requires a bipolar...
The following is a github repository with KiCAD files for a dual +/-5V supply that can be driven from USB power.
github repository for dual supply
When designing for microcontroller boards, it is tempting to try to do as much as you can with...
One thing to think over is that the Teensy 4.1 is not 5V tolerant so if at some time you have accidentally pulled up to 5V maybe you have damaged the I2C bus IO on the Teensy?
Do you have an DSO or logic analyser to look at the signals?
That looks correct.
However one issue you need to be very careful of is ensuring that SDA and SCL are not pulled up to or being driven to 5V. Is your ADC running off 3.3 or 5V?
They can also save the cost of providing technical support by tricking their customers into asking you for support.
If your product becomes successful enough that it's resold through dealers or distributors, then you'll have a very difficult...
Hi Paul,
I don't have any issue with the process you have created at all. My question for the forum is how important people feel it is to use this for a product that is going out to consumers.
One thing that does weigh into this a little is the...
Hi Smuscat,
Recommend you look at the pullup resistors as well (not sure if you have done so?)
Are your connections made to the SDA0 and SCL0 pins? This is important as you have not defined pins other than default in your code.
I also not that...
Hey Mark,
Thanks for your considered response.
Your product sounds very nice!
I can see for products that have actuators or potential safety issues then preventing other versions of firmware from being loaded is a very good reason to enable...
I have a product I've developed for which I use the Teensy 4.1, it is a data acquisition and related product.
I was initially planning to provide these with the locked version of the Teensy 4.1 so I could prevent people from copying the firmware...
Hi smuscat, I have done this exact thing recently and managed to have it working well now.
I would check that you have appropriate pull up resistors on the I2C lines. I had 4k7 resistors and was running a clock freq of 400kHz and with the length...
I have used these in a few projects and use the output do supply a buck converter that supplies 5V to my board including the Teensy 4.1
https://www.digikey.com.au/en/products/detail/abracon-llc/ARJM11D7-114-AB-EW2/7675220
One could design a...
I have dug through this forum a bit, and I know that this has already been brought up a few times, but I want to write my own plea. I have been using a teensy 4.1 for a formula SAE project to create a custom ECU for an electric vehicle. It was...
Well damn, this turns out to be a simple (albeit very timewasting) typo.......
There is no factstical pointer issue, just a screwup with the index calculation...
Another data point, I am passing a huge 16Mbyte array I have defined as;
EXTMEM volatile uint8_t bigbuffer[BIG_BUFFER_SIZE]; // 16Mbytes as single bytes
To a function defined as:
void megunoLinkChartHSLoggedData(Stream* port, loggerConfigType*...
Hi All,
I have a curious corruption of a failry large ram buffer defined in my project running on a Teensy 4.1 with numerous libraries, high speed ISR driven by ADC interrupts etc.
This one has got me stumped as it is reliably corrupting it...
So have had a rather unexpected issue with my code after implementing the TEENSY_OPT_SMALLEST_CODE flag.
I was having all sorts of issues with floats not being handled as expected using printf.
Unexpected problems like incorrect chars and the...
Thanks guys.
I have tried just changing the optimisation flag to TEENSY_OPT_SMALLEST_CODE (Iam using Platform IO) and this has reduced the RAM1 usage for code by a bit over 100kB :-)
I'll go through and change as many functions to use the...
Hi All
I have a project using a Teensy 4.1 with many peripherals, quite large line count and numberous large buffers used for logging multiple peripheral data streams.
It seems I have something going on in my code that is using a very large...