USART2 setting for 1MHzCPU + 4PLL

[rmteo]

AS further test i built another blank board last night , placed only the 3.3v regulator on , smoothing caps and the cpu
programed the cpu with config , of 64mhz, shut down all services inside the cpu
and did a loop of pause in the main ( eg do nothing
the draw current was - 10ma

if you able to get the figures you suggest in real world then please try cos i cant

cheers

Sheldon

The figure you are seeing is exactly what the data sheet says, run current at 64MHz should be in the range of 7-12mA. Put the MCU to SLEEP and see if it goes down to <10uA range - if not then it is not in SLEEP mode.

Then re-design your application such that it stays in SLEEP mode until it needs to do something useful. ONLY then should it wake and run at full (64MHz) speed, then immediately go back to SLEEP - no waiting in a delay for something to happen. As Richard said, waiting in a delay is not doing anything useful, it is just burning CPU cycles (at full speed and wasting power). This is the proper way to use the low power modes of any MCU and you should then be able to able to get the average run current down to the sub 0.2mA range for operation with coin cells.