Problem in replacement of Atmega88-20AU

[homesh]

Dear Friends ,
I have one product using Atmega88-20AU . It is already working , but now I cannot find Atmega88-20AU in stock . So , buy a Atmega88AP-AU which i read is equivalent to Atmega88-20AU from this site "http://www.katalog.micros.com.pl/katalog_en.php?kat=089073077" . But Now facing problem --It Programmed Successfully but after that working of product is not as it may be .--like gate pulse is not having ON-OFF time same as in program and also output from other pins are different . I cannot understand , what is happening ? If i cannot use this uC in replacement of Atmega88-20AU .Please Someone help me for this ..
THANKS IN ADVANCE .
                              Sorry to moderator team , if I post topic in wrong Board . That is because i do not know if this problem is related to Programming or to Hardware .

[mhemara]

Atmega88-20AU is available & still in stock   
Select your desired distributer

http://www.newark.com/jsp/search/productdetail.jsp?SKU=01M6912&CMP=AFC-SF-T21
http://app.arrownac.com/aws/pg_webc/0,1086,,00.html?application=SEARCH&appid=nac&event=1020&docid=41667152S7279084N3744
http://avnetexpress.avnet.com/store/em/EMController/_/A-3576185/An-0?action=part&catalogId=500201&langId=-1&storeId=500201&CMP=KNC-Supplyframe_VSE-T21

Best regards

[Mega32]

@Homesh

Did you remember to set the fuses correct ?

An ATmega fresh from the factory , will run default 1Mhz from it's internal oscillator.


Have a look in these two appnotes as you go from mega88 to mega88P and at the same time
from mega88P to mega88PA.

AVR512: Migration from ATmega48/88/168 to ATmega48P/88P/168P
http://www.atmel.com/dyn/resources/prod_documents/doc8035.pdf

AVR528: Migrating from ATmega48P/88P/168P to ATmega48PA/88PA/168PA
http://www.atmel.com/dyn/resources/prod_documents/doc8196.pdf

Mega32

[jestanoff]

Here's another link with the stock of Farnell
http://uk.farnell.com/atmel/atmega88-20au/8bit-8k-flash-mcu-smd-tqfp32/dp/9171487