by looking at the boards.txt from the zip in the json link i just posted i came up wiht this json
i simply took the sanguino_atmega644.json file and edited it with what i think is correct
{
“build”: {
“core”: “arduino”,
“extra_flags”: “-DARDUINO_AVR_SANGUINO”,
“f_cpu”: “20000000L”,
“mcu”: “atmega644”,
“variant”: “sanguino”
},
“frameworks”: [
“arduino”
],
“name”: “OMC with Atmega644 at 20Mhz”,
“upload”: {
“maximum_ram_size”: 4096,
“maximum_size”: 63488,
“protocol”: “stk500v2”,
“require_upload_port”: true,
“speed”: 115200
},
“url”: “”,
“vendor”: “”
}
does it look somewhat correct? and what about pin connections?