Coming Soon: Teensy-LC (low cost Teensy)

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Paul

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Teensy-LC (low cost) is coming in about 1 month (edit: Release is scheduled for March 10th), featuring a 32 bit Cortex-M0+ processor at 48 MHz, 62K flash, 8K RAM, and a rich hardware peripheral set.... at a retail price of $11.65 (usd).

High-res Photo:
teensylc_front.jpg
(click for full size)

First Prototype:
teensylc.jpg

As a special thanks to very active forum contributors and library authors, we're making an early, hand-soldered pre-production run. PJRC will send free Teensy-LC prototypes to these people:

cartere, christoph, Constantin, duff, el_supremo, embedded-creations, Experimentalist, Frank B, GremlinWrangler, Headroom, JBeale, jimmayhugh, johnnyfp, Jp3141, kriegsman, KurtE, linuxgeek, manitou, MichaelMeissner, MickMad, mortonkopf, mortonkopf, MuShoo, mxxx, Nantonos, nlecaude, nox771, onehorse, Pedvide, Pensive, pictographer, potatotron, robsoles, stevech, sumotoy, syso2342, teachop, tlb, turtle9er, whollender, WMXZ, Wozzy, xxxajk

We'll start with 9 purple prototypes, next week, and the rest with green prototypes in about 2 weeks. I'd like to invite everyone on this list to reply with something like "I have time to beta test now, please send me one of those first 9 boards", and if outside the USA, "I can pay the extra fees+duty UPS charges when delivering the package". Otherwise, we'll send you a green prototype in a couple weeks... still well before the regular production boards go on sale.

Over the last several weeks, many small hints have been dropped. Now, finally, here's detailed technical information:

Edit: An official Teensy-LC web page is now available, as well as a pre-order product page.

Teensy-LC is based on Freescale part MKL26Z64. It has 64K of flash (2K is reserved for emulating 128 bytes EEPROM) and 8K of RAM. A total of 27 digital I/O pins are available, 4 with 20 mA drive capability, the rest with 5mA output. Most pins have interrupts.

There are 13 analog inputs, 8 PWM outputs, and one 12 bit DAC output.

Plenty of serial communication ports are available. There are 3 hardware serial ports, 2 SPI ports and 2 I2C ports. Of course, Teensy-LC has DMA-based hardware USB, for very efficient USB communication that can support all the same USB options as Teensy 3.1.

A 5V output buffer is provided for pin 17, to output a 5V logic signal useful for driving WS2812/NeoPixel LED strips.

The goal behind Teensy-LC is to give you as many features, enough memory for Arduino compatibility, and as much performance as possible, at a great price. But some features of Teensy 3.1 simply aren't available at this lower price point. The I/O pins are not 5V tolerant. The maximum speed is only 48 MHz, and the Cortex-M0+ omits M4's special math instructions. CAN bus is not available. Teensy-LC has only 4 lightweight DMA channels, rather than 16 fully featured channels. Serial1 & Serial2 have only standard buffers, not FIFOs. A total of 7 hardware timers are available, enough for excellent Arduino compatibility, but fewer than the 12 in Teensy 3.1.

Teensy-LC is designed to be pin-compatible with Teensy 3.0 and 3.1. This table shows which pins have which features:

Code:
Pin     Analog  PWM     Serial  SPI     I2C     INT     Touch   Out Drive
---     ------  ---     ------  ---     ---     ---     -----   ---------
 0                      RX1     MOSI1                   Touch   5mA
 1                      TX1     MISO1                   Touch   5mA
 2                              CS0             INT2            5mA
 3              PWM                             INT3    Touch   5mA   (driven high during upload)
 4              PWM                             INT4    Touch   5mA
 5                                              INT5            20mA
 6              PWM             CS1             INT6            5mA
 7                      RX3                     INT7            5mA
 8                      TX3                     INT8            5mA
 9              PWM     RX2                     INT9            5mA
10              PWM     TX2     CS0             INT10           5mA
11                              MOSI0           INT11           5mA
12                              MISO0           INT12           5mA
13                              SCK0            INT13           5mA
14      A0                                      INT14           5mA
15      A1                                      INT15   Touch   5mA
16      A2      PWM                                     Touch   20mA
17      A3      PWM                                     Touch   20mA + 5V:8mA
18      A4                              SDA0            Touch   5mA
19      A5                              SCL0            Touch   5mA
20      A6      PWM             SCK1            INT20           5mA
21      A7                                      INT21           20mA
22      A8      PWM                     SCL1    INT22   Touch   5mA
23      A9      PWM                     SDA1    INT23   Touch   5mA
24      A10                                                     5mA
25      A11                                                     5mA
26      A12/DAC                                                 5mA
 
Wonderful!

I have time to beta test now, please send me one of those first 9 boards!

Probably too late but here I am anyway!

Yay, two SPI ports!

What are the double row of pins between pin 20 and 3V3? Oh pins 21-26, of course!

And what are the pins at the non-USB end, still DAC/PROGRAM/GND/3V3/VBAT?

And no pin pads on the bottom?
 
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cool, sign me up! This will perfect fo my SDI-12 sensor controller! Is there a reference manual on your site yet?
 
Hey that is so awesome. Look forward to harassing the latest baby in the Teensy family. :D

Keep warm everyone in the NE, we may get as much as 3' of snow tonight! Wind is blowing pretty good already. All batteries charged!
 
Count me in. Perhaps first try RadioHead. Should work, as RH squeezes into a mega328 with ease (in terms of RAM). I can have the Teensy-LC w/RH talk to other RH boards I have running: Mega328, Teensy 3, and some M4s using CMSIS/HAL with RH.

No FIFO on UARTs. Is there DMA for UART transmit?
 
Thanks! I was actually going to PM you (Paul) today to ask about availability -- I have an upcoming project that I can begin testing with immediately.

I apologize if this has already been discussed, but there's no built in RTC so you'd need something like a DS3231?

Looking forward to testing the new boards.
 
I can wait for others with a more pressing need than me to get the early boards. Thanks by the way. I hope I have unpacked my soldering station by then (I had to pack up the soldering station when we set up the Christmas tree, on orders of SWMBO [she who must be obeyed]).

I assume that the pin 17 output on the back will put out VIN and not 5v, so if I power the normal VIN with with a Lipo battery, it will be 3.7v (i.e. it is a MOSFET or equivalent, and not a 3.3->5v boost circuit).
 
Hey thanks!

On 8 weeks leave with intention on getting into some meaty projects, so happy to work on the bleeding edge. Do note my code Fu isn't what I'd like it to be so when prioritising your shipments stick me in the 'happy to legwork through existing libraries' group rather than 'can spin code from the raw aether' class.

Edit, happy to pay postage seeing as it's coming most of the way round the world to >40C country. I assume I can make an ordinary order and have it packed in with that?

GW
 
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Thanks! I'm delighted. I'd be able to do light testing on touch sensing, the DAC, and the audio library. I would put myself low on the priority list because I'm not the author of any of the major hardware-oriented libraries. I could also do proof-reading if there's any documentation that needs it.
 
Also thanks! I can do some testing, but I'd rather have the green board in a couple weeks - currently in the middle of moving.
 
Hi Paul,

thank you, great.

But I'll wait for a green board.
UPS to Germany is $73, and Airmail takes several weeks, so its better give the first prototypes to other recipients.

Regards,
Frank.
 
Thank you, but I second that - give the boards to those who can deliver feedback faster and cheaper. I'm looking forward to the green one.

Regards

Christoph
 
I have time to beta test now, please send me one of those first 9 boards.

I'll do my usual broad but not deep tests that I do for "comparative anatomy" of various MCUs
 
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Thank you Paul,

I don't have that much time to be a beta tester, but I'll make sure the ADC library works as soon as I get the green prototype.
 
Thanks, Paul! Never actually expected to be one of those 'top contributors!'

If there's still any available, I should have time to beta test now. I'll probably do some MIDI tests (especially to see how difficult it'll be to get it running my 3x-ports HID descriptor setup), and perhaps using it as a brain for a bluetooth-based lighting control system I've been mulling over. If not, I can most certainly wait for a green board.
 
Hi Paul,

thank you, great.

But I'll wait for a green board.
UPS to Germany is $73, and Airmail takes several weeks, so its better give the first prototypes to other recipients.

Regards,
Frank.

Idem,
shipping to Italy is even worse than to Germany. So give first prototypes to people who actually build something in the past and are within shipping days and not shipping months.

Maybe, all experienced users could check the specs and share with us ideas that may be useful for the Teensy-LC. I have first to spin-up my gray cells.
 
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Yes, and DMA, so I'll have to think about how to support two SPIs in that library without duplicating lots of code.
 
Looks like there might be more than 9 requests for the first 9 boards. If that happens, Robin & I will use some highly arbitrary (and probably unfair) process to decide who gets the first 9 boards. Please bear with us and understand we're doing everything we can. The rest of the boards will be here fairly soon.

Now, let's see if I can get all the questions answered quickly.....

No FIFO on UARTs. Is there DMA for UART transmit?

Yes, there's DMA, but I'm not planning a DMA-based UART driver.

If anyone contributes such a thing, I'll probably merge it into the code. Odds are strong such code would be disabled by default, so editing a #define would be needed.

Edit: I should also mention, if you're doing high baud rate serial communication and also stuff concurrently, odds are good you'd want the extra RAM and much faster CPU of Teensy 3.1 anyway!


but there's no built in RTC so you'd need something like a DS3231?

TL;DR = correct, there's no RTC. You'd need an external RTC chip.

If you read the chip's reference manual, or perhaps overly-optimistic marketing literature from Freescale, you'll see a RTC is mentioned. But there's no separate oscillator or dedicated power domain, so it's pretty much worthless. As a general rule, PJRC tries very hard to promote realistic expectations, so we won't be mentioning the RTC.


I assume that the pin 17 output on the back will put out VIN and not 5v, so if I power the normal VIN with with a Lipo battery, it will be 3.7v (i.e. it is a MOSFET or equivalent, and not a 3.3->5v boost circuit).

Correct, the buffer is powered by VIN, so the output high voltage will be whatever your VIN voltage is. There's no boost converter.

UPS to Germany is $73, and Airmail takes several weeks, so its better give the first prototypes to other recipients.

PJRC will pay for UPS shipping if you want one of those 9 boards. But you'll have to pay any extra fees UPS charges when the package arrives. Sometimes those extra fees can be substantial.

Frank, you've done so much great work. I'm happy to pay for the UPS shipping if you want one of those first 9 boards. If you want one, don't be shy!
 
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I'm thrilled to be listed, and excited by the feature set at such a low price point.

Priority for the first 9 should go to others who are closer geographically so that the lead time isn't burned up by transatlantic shipping. Besides living in France, I will be in Australia on business from 4 to 16 Feb. So it makes more sense to put me in the second batch.
 
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