Teensy 3.6 diy board

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It depends on the used crystals. With the crystals from reply#22:
16Mhz: 2x20pF
32kHz: none

HWGuy thanks for your answers.
Why the crystal 32kΗz he doesn't want capacitors?
By what criteria we choose if we will do or not capacitor?
For example the crystal wants;
 
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Here Paul recommends 20pF load capacitors for a 18pF crystal (Teensy 3.1): https://forum.pjrc.com/threads/27378-Teensy-3-x-Crystal?p=60672&viewfull=1#post60672

The 16MHz crystal on the Teensy 3.2, 3.5 and 3.6 has a load capacitance of 9pF.

For example the crystal wants;
no additional load capacitors needed

Paul recommends a 12.5pF crystal for RTC (Teensy 3.0): https://forum.pjrc.com/threads/724-...-3-0-RTC-questions?p=1561&viewfull=1#post1561

4CfBLv9.png


the load capacitors are calculated with this formula

CX = 2 * CL - CPARA - CINT
19pF = 2 * 18pF - 7pF - 10pF



 
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Here Paul recommends 20pF load capacitors for a 18pF crystal (Teensy 3.1): https://forum.pjrc.com/threads/27378-Teensy-3-x-Crystal?p=60672&viewfull=1#post60672

The 16MHz crystal on the Teensy 3.2, 3.5 and 3.6 has a load capacitance of 9pF.

no additional load capacitors needed

Paul recommends a 12.5pF crystal for RTC (Teensy 3.0): https://forum.pjrc.com/threads/724-...-3-0-RTC-questions?p=1561&viewfull=1#post1561

4CfBLv9.png


the load capacitors are calculated with this formula

CX = 2 * CL - CPARA - CINT
19pF = 2 * 18pF - 7pF - 10pF




Why a teensy 3.2,3.5 and 3.6 there are no capacitors in the crystals?
 
Why a teensy 3.2,3.5 and 3.6 there are no capacitors in the crystals?
Think about it!
maybe they are not needed. Maybe they are chosen the way, that sufficient capacity exists (internal and external).
(HWGuy gave you a formula)
BTW, search the forum for other successful DIY approaches, which also discuss the actual 3.2 designs. It really helps.
 
They're built inside the chip. In fact, there's 4 capacitors inside the chip, 2pF, 4pF, 8pF and 16pF, which can be turned on/off by software control.

Thanks paul.

regarding the circuit in reply #24

have a look at the "Recommended connection for unused analog and digital
pins" section in the K66 datasheet. http://pjrc.com/teensy/K66P144M180SF5V2.pdf page 79 & 80

for example:
VREFH - Always connect to VDD potential
VREFL - Always connect to VSS potential

HWGuy thanks for clarifying,the schematic in post 24 is not the final.
Just i did the most simple schematic to see if can the bootloader chip to programming the MK66FX1M0VLQ18.
 
if there's going to be custom boards, we'll need the bootloader chips to be compatible with the k66 mcu (the pjrc page says it's only up to teensy 3.2)
 
if there's going to be custom boards, we'll need the bootloader chips to be compatible with the k66 mcu (the pjrc page says it's only up to teensy 3.2)

I also want to build a custom board and don't know if i can order the bootloader or not.
Just forgot to update the website or are the bootloader still not available for the "teensy 3.6" custom boards?
Thanks
 
They're built inside the chip. In fact, there's 4 capacitors inside the chip, 2pF, 4pF, 8pF and 16pF, which can be turned on/off by software control.

Hello after a long time,the crystals 16Mhz and 32.768kHz what load capacitance it must have everyone??

Thanks.
 
About 8 to 10 pF for 16 MHz and 12 or 12.5 for 32.768 kHz.

Crystals with higher capacitive load specs can be used, but you'd need to edit the default code or add external caps.
 
Hello,
i want to use the pins PTA6,PTA7,PTA8 of the microcontroller MK66FX1M0VLQ18.I want to declare these pins as INPUT_PULLUP as in the example below:

pinMode(21, INPUT_PULLUP); //exmple to 21 pin

Τhese pins PTA6,PTA7,PTA8 are not registered with some number,these pins correspond to a number or because they are not available on the board teensy 3.6(version MK66FX1M0VMD18) they have not been registered??

A solution is to state it:

PORTA_PCR6 = PORT_PCR_MUX(1) | PORT_PCR_PE | PORT_PCR_PS;
PORTA_PCR7 = PORT_PCR_MUX(1) | PORT_PCR_PE | PORT_PCR_PS;
PORTA_PCR8 = PORT_PCR_MUX(1) | PORT_PCR_PE | PORT_PCR_PS;

Correctly?
 
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Looks correct to me...

Probably more work than benefit, but you could of course also update your setup to have more registered pins. Like maybe create a new Variant in boards.txt...

Then update the pin Tables...
Would probably require changes to:
Code:
core_pins.h - Add in the info about the new pins (pin, mask, port register, ...), and counts - not hard but tedious. 
pins_arduino.h - If you want some of them to work as Analog pins
pins_tensy.c - to add to bitband.
 
I will try it kurte thanks.:D
One last question,on the pins i mentioned above i will put push buttons.
I am thinking of turning on the internal pullup resistors on these pins and do not put external pullup resistors,i will not have a problem properly?
 
If you don’t find the answer in the reference manual, you can still try to activate the GPIO MUX for these pins, configure their port control registers for the internal pull-up, let the code run doing strictly nothing and check the differential inner resistance with a resistor towards ground and a multimeter. Learning by doing is the preferred way to go!
 
Generally when we want to use push buttons it is good to use internal pullup resistors or to mount external pullup resistors??
I'm asking why in my project i have activated the internal pullup resistors.Like here.
 
I have had reasonable luck using the internal weak pull up resistors for things like buttons. You simple need it to be strong enough to register as a high if using PU or LOW if PD...
 
Hello,
i want to use in my project the function hibernate to have very little consumption.
I found this voltage regulator which has very low quiescent current but it's very low output current 85mA.
In my project i use two channels spi,three channels uart,three analog port,one channel i2c,sd card,one dac port and 24 io port,all peripherals and sd card powered from another voltage regulator.
The 85mA output current which gives is enough or i will need more??I use the teensy 3.6.
 
Hello,
i want to use in my project the function hibernate to have very little consumption.
I found this voltage regulator which has very low quiescent current but it's very low output current 85mA.
In my project i use two channels spi,three channels uart,three analog port,one channel i2c,sd card,one dac port and 24 io port,all peripherals and sd card powered from another voltage regulator.
The 85mA output current which gives is enough or i will need more??I use the teensy 3.6.

May not be sufficient. over 100 mA @ 5V is frequent observed when writing to uSD.
 
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