MP2949a Chip firmware

Hello! I bought 7pcs. MP2949a chips, the programmer does not see any of the chips. I have a chip removed from a faulty board. Under the same conditions, this chip is detected by the programmer. Is it possible that the new chip requires some kind of initialization, or was it simply that they sent me junk instead of chips? What are the necessary and sufficient conditions for connecting the chip and the programmer?
Best wishes. Igor.