Search found 17 matches

by Beowulff
Sat Jun 06, 2020 5:56 pm
Forum: Hardware
Topic: DAC has a lot of offset
Replies: 1
Views: 2330

Re: DAC has a lot of offset

I wasn't able to find any suggestions on how to fix this, so I added a small positive bias voltage to the non-inverting input of my Op Amp signal conditioner. This fixed the problem, but at the expense of a new board revision, and some reduced dynamic range (zero volts out now starts at a DAC count ...
by Beowulff
Fri Jun 05, 2020 4:37 pm
Forum: Hardware
Topic: Which FTDI and jumper wire to buy
Replies: 1
Views: 3143

Re: Which FTDI and jumper wire to buy

No reason this shouldn’t work.
As for jumper wire - any small insulated wire will do. I bought a package of various multi-color jumpers with M-M, F-F, and M-F pins. Very handy.
by Beowulff
Fri Jun 05, 2020 1:04 am
Forum: Hardware
Topic: PCB Antenna Tuning
Replies: 4
Views: 5419

Re: PCB Antenna Tuning

Look here: https://www.ti.com/lit/an/swra638/swra6 ... 1318797718

But, this going to be an approximation at best. Once you get close, you are going to need to make a board and actually measure it’s performance.
by Beowulff
Thu Jun 04, 2020 11:02 pm
Forum: Hardware
Topic: DAC has a lot of offset
Replies: 1
Views: 2330

DAC has a lot of offset

Has anyone else experienced this?
Both DAC channels have between 4 and 10mV of offset when they are supposed to be at zero volts.

This is a problem for me, since I really need the output to go to zero when it is supposed to.
by Beowulff
Thu Jun 04, 2020 11:00 pm
Forum: Hardware
Topic: RS422 vs RS485 for newbie
Replies: 1
Views: 4412

Re: RS422 vs RS485 for newbie

I don't understand the question, but RS485 is a bus and RS422 is point-to-point.
Both are differential, but the protocols are generally much different.

A better diagram, and clearer explanation of what you are trying to do would help.
by Beowulff
Mon Mar 04, 2019 3:25 pm
Forum: ESP32 Arduino
Topic: [SOLVED] void loop() doesn't detect button release ?
Replies: 6
Views: 8363

Re: void loop() doesn't detect button release ?

You need to loop while the button is pressed, and wait for it to be released.
by Beowulff
Fri Mar 01, 2019 3:09 am
Forum: ESP32 Arduino
Topic: How do I modify the uart ISR?
Replies: 0
Views: 2093

How do I modify the uart ISR?

I have some very tight serial timing requirements. Once I receive a command byte, I need to respond within 2mS. By setting the FIFO Full level to 1, I am able to do this most of the time, but there are still occasional delays that cause the response time to exceed my requirements. I would like to mo...