Post Created date
ATmega48 - AD5121 I2C problem
I suggest you start using analog channels/probes on the scope to debug I2C instead of digital channels, as you cannot see the underlying analog signal. You would have much better...
Tue. Aug 26, 2014 - 02:38 PM
ATmega48 - AD5121 I2C problem
It's more simple than you think. Chip datasheet says it uses 7-bit addresses in the 0x20 range. Arduino wire library wants 7-bit addresses (0x2F). But what you must write to data...
Tue. Aug 26, 2014 - 09:10 AM
MCU as SPI slave, not easy?
Thanks everyone for ideas, I had other issues keeping me busy and away, I apologize. Indeed the replaceable chip is an MCU which has SPI but it is suboptimal and has all kind of...
Tue. Aug 26, 2014 - 09:02 AM
proplem with program code on atmega8
JonikS wrote:js wrote:Quote: _delay_ms(viive); What is viive? Not a variable I hope. Actully it is, i use it to make led blink faster or slower. Should i avoid implementing it...
Tue. Aug 26, 2014 - 06:21 AM
[help] I give up... ADC to serial
1) what is the clock source? internal oscillator? are you absolutely sure the AVR is really running at the speed you think? have you verified this and how? did you blink a led at...
Mon. Jul 7, 2014 - 07:39 PM
I2C/TWI cable distance
I2C specification facts: -at least 3mA max pull-up current for normal devices -400pF max bus capacitance (wires, pcb, chips, everything) -normal 100kHz speed standard allows up to...
Sun. Jul 6, 2014 - 07:18 PM
TWI SDA/SCL pulled low by un-powered ATMega48???
Yes the TWI bus is definitely trying to power the unpowered AVR through the IO protection diodes. You are not supposed to do that, leaving unpowered devices that have clamping...
Sun. Jul 6, 2014 - 06:29 PM
Mega164 -- ADC affects pin change?
If you cannot see a spike on scope right at the MCU pin, then it is something internal. But it is not a first time that sampling with ADC will cause spikes but usually they are...
Thu. Jul 3, 2014 - 10:17 AM
TWI - Pull up
Nothing is ever allowed to pull lines high, except the resistors.
Tue. Jul 1, 2014 - 06:40 PM
driving a 12V LED from atmega1284p
So you are exceeding the IO pin current absolute maximum limit nearly fourfold (about 150mA for LED, 40mA max limit). I am surprised the AVR still works and is not broken. Even...
Thu. Jun 26, 2014 - 02:09 PM
arduino dimmer
Max supply voltage VDD is 5.5V and you can't have voltage over VDD+0.3 on wiper pins or it will blow. So when using Arduino, you have 5V supply and wiper pins must be within...
Wed. Jun 25, 2014 - 09:47 PM
driving a 12V LED from atmega1284p
Well the problem is not on this picture. If READY signal low is 1.78V then it is a problem. Normally 5V logic signals are either 5V or 0V or very near it, not 1.78V. The...
Wed. Jun 25, 2014 - 06:47 PM