A handful of newb Teensy 3.2 questions

Status
Not open for further replies.
I

Involute

Member
If these sorts of things are addressed somewhere, feel free to point me to the appropriate reference.

1. Is it true that I can power the Teensy with 5V at the Vin pin?

2. What's the difference between the GND pin next to the USB connector and the GND pin next to the button?

3. What's the purpose of Vbat? My application is battery-powered, but it's a 12V battery driving a 5V regulator; I assume Vbat is for monitoring a coin cell or something similar.

4. Am I correctly interpreting table 4 on page 13 of the datasheet (for the MK20DX256) as saying the maximum sink and source current for a single IO pin is 9 mA (I assume the ARM on the Teensy is supplied with 3.3V from the regulator)?

5. When I compile my application in the Arduino IDE, a little Teensy window pops up telling me to press the button on the Teensy to program it. I seem to be able to download sketches without having to press the button. What's the purpose of this window?

Thanks.
 
1) yes
2) same
3) coin cell
4) yes yes
5) this is the loader to write your arduino sketch to teensy using rawHID protocol, since the IDE cant do it on its own
 
Thanks again, tonton. Re 5., what's the process then for uploading a sketch? There's the button on the Teensy, a green button in the loader window, and <CTL>U in the IDE. It's not clear to me what the order is.
 
just program it like its an arduino, the loader is automatic and uploads by itself :)

the button puts it in program mode, but you wont need to use it once you load a sketch on
 
Re the button, normal method is to just hit compile in Arduino and let it do everything, but if you manage to put an impossible config on the Teensy, say setting deep sleep or nostandard clock rate the button is a backup to force sane values and program mode.
 
tonton81 said:
just program it like its an arduino, the loader is automatic and uploads by itself :)

the button puts it in program mode, but you wont need to use it once you load a sketch on
Click to expand...

As long as the Teensy has a running USB aware sketch. If sketch faults, speed too low for USB, or compiled with NO USB under tools.
 
Others have answered some of the questions, so I will delete those.

Involute said:
If these sorts of things are addressed somewhere, feel free to point me to the appropriate reference.

2. What's the difference between the GND pin next to the USB connector and the GND pin next to the button?
Click to expand...

The ground pin next to pin 0 (first pin on the right if you are looking at the teensy with the USB connector down) is the same as the ground pin on the back.

The analog ground (2nd pin on the left) should only be used with analog inputs.

Involute said:
3. What's the purpose of Vbat? My application is battery-powered, but it's a 12V battery driving a 5V regulator; I assume Vbat is for monitoring a coin cell or something similar.
Click to expand...

If you solder a 32.678 kHz crystal to the 2 pins on the center of the Teensy 3.2, you can connect the Vbat pin in the back and a ground pin to a 3v coin cell battery, and the coin cell will keep the real time clock within the Teensy powered, even if the main Teensy is not powered. Vbat is only for the real time clock.
 
Involute said:
What's the purpose of this window?
Click to expand...

Teensy Loader is the program which actually does the uploading to your Teensy board.

Most AVR-based boards (Arduino Uno, Mega, etc) use a program called AVRDUDE. Arduino Due uses one called Bossa. Most of them are just command line utilities with text-only interface, so you only see their info in the console part of Arduino's main window.

Teensy's program is GUI based. It can also be used stand-alone, to program Teensy with your HEX file if you produce it from some other software than Arduino, or if you wish to share the HEX file with others to program on their boards.
 
Status
Not open for further replies.
Back
Top