17
votes
Accepted
_delay_ms() is much slower than expected (by a factor of 6) on TinyAVR 0/1 (ATTiny1604)
Your toolchain is not broken. In the ATTiny804/1604 datasheet, page 77, it shows the CPU clock is divided from the 20/16 MHz oscillator by a prescaler (the ATTiny1614 datasheet shows the same clock ...
- 439
14
votes
Accepted
Does the Arduino Uno have two crystals?
The ceramic resonator in yellow is connected to the main MCU, and the crystal in red is connected to the other MCU. USB requires tighter tolerances than is available from a resonator therefore a ...
- 17.7k
9
votes
Accepted
Arduino 16 MHz with only 3.3V?
Officially, no. Practically, often but not always.
If I follow the datasheet to the the letter, this configuration should not work. BUT... After some test, it did work.
The data sheet does not ...
- 5,401
5
votes
Programming standalone Atmega328p-PU with NE555N timer IC
No, you won't be able to build a 16 MHz clock signal using a 555 timer. That's far beyond the 555 capabilities (see N.B.).
If you could squeeze out of the 555 a mere 1 MHz (which I seriously doubt), ...
- 2,114
5
votes
Accepted
How can you reduce the clock frequency of an Arduino Mega?
You can set the clock prescaler for that:
void setup() {
noInterrupts();
CLKPR = _BV(CLKPCE); // enable change of the clock prescaler
CLKPR = _BV(CLKPS0); // divide frequency by 2
...
- 43.9k
5
votes
Arduino 16 MHz with only 3.3V?
According to the datasheet you need 3.78V to run at 16 MHz, and 3.3V isn't that far off. I would be surprised, for example, if it stopped working at 3.77V, because that would mean that the operating ...
- 38.5k
4
votes
Arduino 16 MHz with only 3.3V?
A little test, not very scientific, but shows it runs fine on 3.3V - https://www.youtube.com/watch?v=If0eOa0Uj5I.
Again, if you would like to stay withing the specification just use a "clock divider/...
- 579
4
votes
Programming standalone Atmega328p-PU with NE555N timer IC
The default configuration of these chips, as they come from the factory,
is to use their internal 8 MHz RC oscillator downscaled at 1 MHz. So you
do not need any extra oscillator to program them.
...
- 43.9k
4
votes
Programming standalone Atmega328p-PU with NE555N timer IC
Yes, you could use a 555. You can also go even simpler and use an RC network. Even simpler still is to use the 1MHz RC network built in to the chip.
The main drawback of these methods, and the 555 ...
- 105k
4
votes
Accepted
Which of the clock sources are actually internal to the ATmega328P?
If it requires a crystal, as the ones in question clearly state, then obviously you need to connect a crystal (and load capacitors). Or use a ceramic resonator.
Only those labelled as internal are ...
- 105k
4
votes
How to divide high input frequency by 1.25 like old-school TTL logic by Arduino?
Your question is a perfect example of an XY problem: you are asking
something that has little to do with your actual problem, but is rather
about your misguided idea of a solution. Counting Mars ...
- 43.9k
3
votes
Atmega328P 8MHz External Clock
The easiest way is to use the settings:
Tools > Board > Arduino Pro or Pro Mini
Tools > Processor > ATmega328 (3.3V, 8MHz)
The problem with that is the Pro Mini bootloader is 2kB and has a bug that ...
- 4,238
3
votes
Programming standalone Atmega328p-PU with NE555N timer IC
It depends on how you're programming it.
If you're using a bootloader to accept programming commands via a serial connection then you will need to use the clock method specified by the fuses ...
- 17.7k
3
votes
Accepted
Change Digispark clock speed, run at low voltage?
You can set the clock prescaler at run time. For example:
#include <avr/power.h>
void setup()
{
clock_prescale_set(clock_div_8);
// etc...
}
More details in the documentation from
avr-...
- 43.9k
3
votes
Accepted
Atmega328P 8MHz External Clock
If you reduce the main clock speed by 50% then everything else is reduced by 50% as well.
The whole chip runs at half the speed. That includes things like the UART.
For example, the bootloader is ...
- 105k
3
votes
Arduino 16 MHz with only 3.3V?
I've built a few 3.3v home-brew-duinos with 16Mhz crystals (because I have a bag of 50 xtals!) - they run fine in the conditions I've put them in so far (on my desk). Some of them may be closer to ...
- 15.3k
3
votes
Does delay() pause the counting of millis()?
Delay uses millis. It just waits examining millis until a certain time has passed.
Millis is driven by an interrupt. The only thing that stops it working is another interrupt (you can only have one ...
- 105k
3
votes
Can the IDE handle a 32khz main clock?
Yes, things will break. The main culpret is this:
#define clockCyclesPerMicrosecond() ( F_CPU / 1000000L )
With any value below 1000000 the result of that calculation will be 0.
That means code ...
- 105k
3
votes
Accepted
Why ESP8266 slower than Arduino nano?
However, despite ESP8266 running at 160MHz, 10 times faster than nano, it's taking 3.5 ms to complete the loop, compare to 2.5 ms than that of nano.
There's a number of reasons for that. Chiefly:
...
- 105k
3
votes
The analog read is not giving the correct waveform as that of an oscilloscope
Your sampling rate is far too low for the signals you are looking at; you're not getting enough data points for drawing something that looks like the original signal.
The Arduino library's analogRead()...
- 1,795
3
votes
Accepted
Is there a way to get about a 10ns Timer resolution from an AVR CPU?
There is nothing you can do on the AVR processors that I know of, which can run on from a quite slow clock, and I think up to 24 MHz. Since your Uno / Leonardo / Micro run at 16 MHz that would be only ...
- 38.5k
3
votes
Is there a way to get about a 10ns Timer resolution from an AVR CPU?
1 ns is a billionth of a second. A 1 gHz clock has a cycle time of 1 ns. If you have a timer that's able to count single clock pulses you'd need a 1 gHz clock to get to 1 ns resolution. for 10 ns, you'...
- 5,702
3
votes
Accepted
Achieving nanosecond accuracy with MKR Vidor 4000
No. You can't.
To achieve 1ns precision you need a 1GHz clock. That can't happen. The MKR Vidor 4000 uses an FPGA with an "A7" speed grade. That means that (according to Table 20 here) you ...
- 105k
3
votes
Accepted
slower clock frequency than expected on attiny202
Just as a complement to chrisl's answer, if you disassemble the compiled
program, you should see that your infinite loop looks like this:
1: sts 0x0407, r24 ; write to PORTA_OUTTGL
rjmp 1b ...
- 43.9k
3
votes
Accepted
Programmer vs target clock frequency
There are multiple ways of programming a 1284P board, such as:
Using the bootloader, via serial input
Using ICSP (via the SPI pins)
High-voltage programming
The bootloader is via a specific baud ...
- 38.5k
2
votes
Accepted
Change from using the external crystal to the internal oscillator
What do I need to change to use the internal oscillator?
You'll need to change the fuses on the chip, and you probably want a new 8MHz entry in boards.txt so that timing functions still work as ...
- 17.7k
2
votes
Change Digispark clock speed, run at low voltage?
The digispark uses the micronucleus bootloader.
You can flash that directly onto an Tiny85 without needing the digispark module. So your existing Tiny85 solution could acquire the USB bootloader if ...
- 6,974
2
votes
Does the Arduino Uno have two crystals?
There are 2 that you can see, but there are internal resonators in both chips. You can use the ATMega328's one if it's on a breadboard (it's half the frequency tho), and much more temperature-...
- 131
2
votes
Atmega328P 8MHz External Clock
Firstly, you can buy 8MHz Atmega328P Pro-Minis from China. They are cheap and run at 3.3V. Look at eBay.
If you want to reduce the power consumption of Arduino boards, you have three primary attack ...
- 256
2
votes
Running quartz clock off an arduino
As I said in my comment, the idea of using the Arduino's own PWM as a
clock source is completely misguided. It will be no more accurate than
using millis() or micros(): both these functions and the ...
- 43.9k
Only top scored, non community-wiki answers of a minimum length are eligible