Yea, so I neeed a pull up resistor

Thanks ^^

So, the minimum circuit for an arduino based development board is a 16MHz crystal and the 100nF cap for power supply and pull up resistor for RESET pin ?

No, you can use the internal oscilator (there is a fuse). And the reset is not required. The minimum is just the cap for the supply

Why reset is not required ? I thought RESET should be pulled up for normal usage ?

Thanks

USBasp consider HVP ? Oh, so for normal usage, I onyl can use 5 pins ?

Thanks

Dear friend,

recently I get myself some attiny85. So, by referring to the datasheet, it mention it has 6 programmable I/O. But I just only can see there are 5 programmable IO only. Is it that the RESET pins also can be the IO  ?

Thanks

But the timing has to be right, hold down the reset, select the program from the IDE, when it says loading, count one two three, and release the reset.

I have tried this ! It's really do work well ! But the timing really have to be correct. Have to release the RESET button once the IDE shows 'uploading..'

Thanks ! Finally I understand why is there a cap there- to bring the RESET High and LOW.

When I want to upload a new sketch, the we should RESET our microcontroller so that the previous sketch is deleted and pull the RESET HIGH to allow the new program to load into ?

Am I correct ?

Thanks !

When will CTS being used ?

Great ! How about CTS? What's that ?

But the timing has to be right, hold down the reset, select the program from the IDE, when it says loading, count one two three, and release the reset.

Great info!!! Will have try it . And let you know soon !

Thanks

If I never connect the DTR pins, I still can load my program to chip using ftdi programmer ?

Does that means that I only have to connect RX, TX , gnd and vcc to MCU?

Why not ? My ftdi programmer have the DTR pins and I am required yo connect it to reset pins via 0.1uF cap..but I do not know why

The capacitor is there to turn the RTS signal into a pulse, so that when the computer brings RTS low, it briefly pulls reset low, and then the pull-up resistor charges the capacitor again, bringing reset high again.

Source : http://www.gammon.com.au/forum/?id=11637

Can anyone tell me about this ? I do not understand why it needs so. And is DTR =RTS ? My FTDI programmer are using VCC, RXD, TXD, DTR,CTS and GND pins

Thanks !

Thanks alot !

Okay. Noted ! If I want to use the analog pins as output pins, so I have to write

Code:

digitalWrite(A0,OUTPUT )

If I were to use it as input pins, however I do not need to define it as its default is input.

Thanks !

Yea, a button to GND and to TX/RX pins should just make it a pull up button right ? So, I think I no need this below code to activate the pull up ?

Code:

digitalWrite(0/1, HIGH)

I am just asking for my own notes so I will becareful when in my project