Go Down

Topic: Creating a standalone atmega2560 (Read 612 times) previous topic - next topic

IdanAbutbul

Iv'e created a schematic and i am wondering if it's working or not,
i am planning to burn to it the arduino bootloader and sketches thru the icsp, will it work?

it's based on arduino mega.

fritzing file attached in zip file.


larryd

No technical PMs.
The last thing you did is where you should start looking.

CrossRoads

C8, C9 are wrong values
Need 10K pullup on reset
Need more 0.1uF decoupling caps, one each on VCC and AVCC - are you showing all the VCC/Gnd pins of the chip?  I think some are missing, pretty sure there are 4 of each.
Add a Gnd near PE0, PE1 for Serial comms for debugging if nothing else.
Perhaps add a DTR pin to 100nF cap to Reset pin for serial code downloading.

Other than that you seem to have the basics down.

You've seen my MegaDip that LarryD linked to,

there also my mini2560:
http://www.crossroadsfencing.com/BobuinoRev17/

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

IdanAbutbul

C8, C9 are wrong values
Need 10K pullup on reset
Need more 0.1uF decoupling caps, one each on VCC and AVCC - are you showing all the VCC/Gnd pins of the chip?  I think some are missing, pretty sure there are 4 of each.
Add a Gnd near PE0, PE1 for Serial comms for debugging if nothing else.
Perhaps add a DTR pin to 100nF cap to Reset pin for serial code downloading.

Other than that you seem to have the basics down.

You've seen my MegaDip that LarryD linked to,

there also my mini2560:
http://www.crossroadsfencing.com/BobuinoRev17/


thanks for your reply, could you please send me or share here the schematic of this?

iv'e searched for it but didnt find

IdanAbutbul

ive changed the schematic and moved from fritzing to eagle,
this is the new schematic:


iv'e added an ftdi, pullup resistor to reset, and changed the crystal, does it will work?

CrossRoads

Looks good.
You  changed the crystal to a resonator? I prefer to stick with crystals.

The RS232, is that real RS232, +/-12V signals? Or TTL levels, 0-5V?
If 12V, the 1K resistors will let up to +/-12mA flow, that will damage the IO pins and potentially the whole chip. You may want to consider a converter chip such as MAX3232 and 5 0.1uF caps
http://www.ti.com/lit/ds/symlink/max3232e.pdf
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Go Up