i been working a lot lately doing some arduino prototypes while learning electronics (as a hobby) and i been moving into creating my own schematics and trying to design my own PCB's now specially trying to move into standalone PCBs running arduino code.
i have succesfully program and burn optiboot into ATMEGA328p chips using arduino as an ISP and i thought that a shield for this could be usefull. attached is an image of the schematic i'm currently using (no PCB yet).
i was wondering if other solution could be achieve that does not require all those dip switches and could be easier to use. like something that could controlled by a push button.
i would like to make my design also program attiny45/85 but i find that dip switches are messy and can be miss configured easily.
i dont have a very big knowledge of electronics parts and i was wondering if there is anything i could replaces the dip switch that could handle the internal logic needed to know if its an attiny45/85 or a atmega328 with something as easy as clicking on a push button.
The 6 pins involved in programing are being connected and disconnected with the dip switches. One row of switches for each chip style. One row are all "on" and the other 2 rows of switches are all "off". You can see what I mean by the picture on this page. http://jeffmurchison.com/blog/arduinoisp-deluxe-shield-updated/
*These 4 pins must only connect to one chip at a time.
*MISO
*MOSI
*SCK
*RESET
These pins can be connected to multiple chips at a time.
VCC
GND
You might be able to use a chip to control which set of pins of the socket are connected.
Here is a google search for a chip with the number 74244 that is capable of multiplixing. I am not sure what to do past that point other than ask for help from other people.
Google link: Google
cyclegadget:
The 6 pins involved in programing are being connected and disconnected with the dip switches. One row of switches for each chip style. One row are all "on" and the other 2 rows of switches are all "off". You can see what I mean by the picture on this page. http://jeffmurchison.com/blog/arduinoisp-deluxe-shield-updated/
Yep, that's exactly how it works (that's my shield design).
OP, if you only want your shield to program ATtiny25/45/85 and ATmega328 then you don't need DIP switches like mine, at the very minimum, you can get away with using only two jumpers (or a small 2-position DIP switch). Here's a reference sheet for the microcontrollers:
Note that the ATtiny*5 pins on the right side (pins 8-5) are:
VCC
SCK
MISO
MOSI
And pins 20-17 on the ATmega328 are the same. So those can be directly connected to VCC, Arduino pin 13, pin 12, and pin 11 (double check that those pins are right, that's off the top of my head and might be wrong).
The only jumpers you would need would be for pins 1 and 4 on the ATtiny*5.
The best and cheapest ISP for the UNO/ATmega328 is a UNO.
I use one of my boards to program up ICs i buy off a Geordie on Ebay for £3 and then install the in my own PCB projects.
he even sends the crystal and capacitors needed for the clock - on his site he also has USB to TTL interfaces for ISP at £9 which includes a blank ATmega328.
The last commercial ISP i bought cost me £200 from Microchip they made it obselete for Win7
