Hi, i was earlier asking about the atmega to do the job, did decide to go 328PB because of fair amount HW pwm's.
today had some time to draw "final" schematic and almost routed the board, but im really unsure of couple of things and might need some help / verification.
First of all the fets, how do i choose correct ones after i know amp/voltage requirements, there is so much stuff in those tiny datasheets that im completely lost in that department..
i was looking at these fets-> http://www.mouser.fi/ProductDetail/NXP-Semiconductors/PSMN1R0-30YLC115/?...
from what i understand i can drive that one with 5v logic, but can it do 12v +4amps as on/off switch and when i PWM it to drive fan speed on DC voltage incase no real pwm control is available for fan attached.
(first attachement is how i was going to use them in circuit)
Second, Does "FTDI FT232RL usb-uart chip" need some kind of external clock? and do i need some extra pin attached if i want to use bootloader, would certainly make sense to have bootloader with this board.
Third thing, im going to use RXD1/TXD1, which are shared pins with MOSI0/MISO0 which i believe are used to program this chip by default, Does this matter since when programmer resets the chip, pins are not initialised for UART anymore, so it shouldn't cause proplems right?
and as last, even thought i did not yet finish routing every wire on the board, someone can propably allready say if its just going to fail no matter what, because i did thing X which i should not do.
Edit: forgot to say, I'm going to switch crystal for resonator, as I have not read too good stuff about the PB models and crystals.