[246] System: Intermittent extra current consumption when going to sleep

[JeanMBoones]

Hi,

[246] System: Intermittent extra current consumption when going to sleep

This anomaly applies to IC Rev. Revision 2, build codes CKAA-Dx0, QIAA-Dx0.

It was inherited from the previous IC revision Engineering D.

Symptoms

Extra current consumption in the range of 350 µA when in System On Idle.

Conditions

A high-speed peripheral (CPU for example) accesses a RAM block which is being accessed by a low-speed peripheral through the DMA bus, with a specific timing, and the high-speed peripheral has higher priority than the low-speed peripheral.

Consequences

Extra current consumption in System On Idle.

Workaround

Apply the following code after any reset:

*(volatile uint32_t *)0x4007AC84ul = 0x00000002ul;

Workaround consequences: Up to 40 µA current increase when the 16 MHz clock is used.

Question

If we use the SPIS to write data via DMA to ram and then we access it with the CPU, can this problem occur?

[Amanda Hsieh]

Hi, 

All peripherals that use DMA are affected though it is very unlikely to happen.

-Amanda H.