Atmega328p chip not recognized by avrdude, and program(led blink) uploaded before was not working either but it did light up the led after 42 sec. and never goes off(so it's kind of working but very very slow?). Everything was fine until I change (fuse) clock from ext. 16Mhz to int. 8Mhz to ext. 16Mhz.
Things I did before bricking the chip,
1. Uploaded led blink program to atmega328p-au chip using usbasp programmer(wired up all connection given in the datasheet and 16Mhz osc.)
2. LED was blinking too fast(almost 100ms) despite having the code with 1s delay
3. Thought 16mhz osc. causing the issue, removed it and pointed clock to internal 8mhz RC by changing fuse(-U lfuse:w:0x62:m -U hfuse:w:0xd9:m -U efuse:w:0xff:m) but led was blinking too slow
4. Searched in google for a solution and found changing bit CKDIV8 might fix
5. Changed the clock source again to ext. 16Mhz osc. (-U lfuse:w:0x60:m -U hfuse:w:0xd9:m -U efuse:w:0xff:m)
6. Avrdude did not recognize the chip, and led blink not happening.