I'm working on upgrading some microcontroller code in a customer's product. One of the sensors which the micro queries is an MPU-6050 on a commodity GY-521 motion sensor PCB. The client sent me three GY-521's for test use. One of them has a part labeled "MPU-6050" as expected, and works as expected. The other two have a part labeled "MPU-6050A" with a different format for the date code than shown in the Invensense literature. I can't find any reference to MPU-6050A being a legit variant of the MPU-6050.
These parts seem to provide the gyro angle readings more or less as expected, but when my driver queries Register 117 "Who Am I" (0x75) the response is 0x98. The correct response would be 0x68. The temperature reading from registers 65-66 is also about 10 deg C higher than expected.
Has anyone else encountered this before? Given the sourcing of the GY-121 boards I don't have a hard time believing that the parts could be sketchy, but it's not like there are a lot of similar parts that could be blacktopped to re-mark as an MPU-6050. If someone was going to the trouble of making full knock-off parts, I'd expect them to get the ID register right.