SparkFun Electronics Comments

SteveB on DEV-13305 - Teensy LC

2016-04-22T10:51:36-06:00

Excellent. Thank you!

M-Short on DEV-13305 - Teensy LC

2016-04-22T08:59:25-06:00

Check out the schematic and if you need more information check out the datasheet for the chip.

SteveB on DEV-13305 - Teensy LC

2016-04-21T22:23:50-06:00

I can’t find the correlation between the digital pin numbers (0-23) and the port registers (PORTA, PORTB, etc.) Can anyone point me in the right direction?

Customer #725309 on DEV-13305 - Teensy LC

2015-10-30T06:11:05-06:00

That certainly is a much more powerful micro for the same price - but the board is 4x the size …

Customer #725309 on DEV-13305 - Teensy LC

2015-10-30T06:08:57-06:00

I’m using a free (code size limit) version or Rowley Crossworks since that’s what I develop on at work (on the paid for version obviously). Install the kinetis support packages for this micro and you’re ready to go. Just remember to #define STARTUP_ON_RESET … anyone who’s used xworks has probably learnt this the hard way :P

Customer #326474 on DEV-13305 - Teensy LC

2015-04-15T13:51:31-06:00

If you want to make 3-50 boards of something and the LC can work, then the $7 price difference adds up.

If you would throw down a simpler arduino, but maybbbbeeee worry about processor overhead, you might want to try the LC.

If you want a 5V pin! There are a couple functional differences on the LC that could sometimes be better than the 3.1 equivalent.

But yeah the 3.1 is a sexy beast to compete with, but I’m just saying that the LC also has its place.

Customer #326474 on DEV-13305 - Teensy LC

2015-04-15T13:49:03-06:00

Belated reply, but Paul/PJRC says that because he’s exceedingly honest. The ADC’s in theory have X-bits, but because they’re jammed on the same silicone as the rest of the processor the reality is you could never expect that. The effective number of bits (ENOB) is then rated more realistically. You can with supersampling expect that maybe you would get better resolution than 12-bit…but you have to know what you’re doing.

Summary: XX-bit (16-bit you said, i haven’t verified) = Manufacturer’s ideal world rating. 12-bit ENOB = realistic rating given by paul

Toni_K on DEV-13305 - Teensy LC

2015-04-06T13:00:00-06:00

Simply a typo on the page. It’s getting fixed!

Toni_K on DEV-13305 - Teensy LC

2015-04-06T12:58:45-06:00

Yo, chill out on the name calling. It was simply a typo that is getting fixed, but please be kind. See the comment guidelines if you need a reminder on this.

TwoCents on DEV-13305 - Teensy LC

2015-04-03T11:45:04-06:00

Shouldn’t this CPU be an ARM Cortex M4? The description indicates ARM Cortex M0. Sorry - was looking at Teensy 3.0

Customer #526247 on DEV-13305 - Teensy LC

2015-03-27T12:21:24-06:00

I am confused about the analog inputs. On pjrc.com (the teensy website) it says the ADC is 16-bit, but the usable/effective resolution is 12-bit. Why is this?

Customer #258806 on DEV-13305 - Teensy LC

2015-03-23T07:53:23-06:00

The FIFO is an extra buffer in hardware. It really helps at fast baud rates, allowing several characters to be buffered in the hardware and all moved to the larger software buffer with only a single interrupt. If other stuff is doing interrupts at higher priority, it allows more interrupt latency from other code before incoming serial data would be lost, or the output fails to keep maximum speed. FIFOs also reduce the total number of interrupts, which is more efficient.

Teensy-LC does not have FIFOs. Neither do any of the normal AVR Arduino boards.

Teensy 3.1 does have FIFOs on 2 of its 3 serial ports. If you’re going to use fast baud rates, especially on 2 ports simultaneously, or in combination with other libraries using a lot of interrupts, the get higher performance Teensy 3.1.

For slow baud rates, like 38400 or less, the FIFOs rarely make much difference.

ChrisBob on DEV-13305 - Teensy LC

2015-03-23T06:35:57-06:00

What does it mean that there are 3 UARTs, but only one has FIFO? Does that just mean that the buffer is handled in software not hardware, or is there a bigger issue I need to worry about?

Customer #258806 on DEV-13305 - Teensy LC

2015-03-22T05:52:26-06:00

There is a Makefile you can use without Arduino. To get it you have to download and install everything, which is a bit wasteful in bandwidth and disk space. After installing, the Makefile in Arduino’s hardware/teensy/avr/teensy3 folder.

Customer #395330 on DEV-13305 - Teensy LC

2015-03-21T22:20:39-06:00

is there a free solution for programming this in C ? not arduino ?

GiladKap on DEV-13305 - Teensy LC

2015-03-21T13:14:57-06:00

It is nice.. but for the same price you can get a 80Mhz M4 (FPU), 2 buttons, LED, full JTAG through USB, development platform, GPIOs, SPI, I2C… http://www.ti.com/tool/ek-tm4c123gxl#buy

uTasker on DEV-13305 - Teensy LC

2015-03-20T18:43:19-06:00

To use the RTC it is best to add a very low power 32kHz oscillator connected to the RTC input pin. Keep the complete circuit powered from a battery and use its low leakage mode to reduce the power to the 1..2uA range. To wake up, a low leakage wakeup (LLWU) input can be used or even an alarm configured in the RTC itself. It is also possible to use the RTC without any crystal by clocking it from the internal LPO (1kHz RC oscillator). This clock continues in the low leakage modes so can also maintain time as in the case discussed previously. It will however have a larger drift than a crystal or external oscillator. More info at http://www.utasker.com/kinetis/KL_RTC.html and http://www.utasker.com/kinetis/LLWU.html There is also a “Teensy LC” simulator at http://www.utasker.com/kinetis/TEENSY_LC.html

Customer #359035 on DEV-13305 - Teensy LC

2015-03-20T08:47:03-06:00

It’s cheaper, sure, but why not spend the extra two or three dollars to just get the 3.1? it’s a really really good board that you can use for all sorts of different things…

Customer #252418 on DEV-13305 - Teensy LC

2015-03-20T03:18:52-06:00

In fact the module has 8 times more memories: 62kB Flash Memory, 8kB RAM. We are engineers, we are supposed to use units correctly, damn it.

jbeale on DEV-13305 - Teensy LC

2015-03-20T00:03:58-06:00

I have one of the Teensy LC beta boards, it works nicely and is of course, cheaper than the Teensy 3.1 if you don’t need the few extra capabilities of its bigger brother.

SlyVixsky on DEV-13305 - Teensy LC

2015-03-19T22:10:50-06:00

hmm…I do stand corrected, thank you.

PickledDog on DEV-13305 - Teensy LC

2015-03-19T17:52:29-06:00

The Teensy LC doesn’t have the spots on the underside of the board to attach the 32kHz crystal - only the Teensy 3 does.

SlyVixsky on DEV-13305 - Teensy LC

2015-03-19T17:11:22-06:00

How is it not relevant? The image in the example link shows exactly where on the underside of the board you need to attach the crystal. Is it really too difficult to break these pins out to use a different crystal? why would you need anything other than a 32Khz crystal, since that’s what ALL RTC products use for time keeping?

Customer #161556 on DEV-13305 - Teensy LC

2015-03-19T17:06:12-06:00

While the micro on the Teensy LC has some RTC hardware it is missing the capability to use an external crystal and as such at least at Mar2015 the linked ‘using RTC’ page was not relevant and the software not supported. Suggest removing the link in the interest of avoiding confusion