Pulls on SPI MISO, MOSI and SCLK when IMP is sleeping?

Hardware
1

In a couple of accelerometers I found that quiescent current is too high when the chip is deselected and when my finger comes near to MISO . This raised a concern, that if IMP is sleeping the pins are floating so that the pin voltage can float to Vcc/2 causing an increased quiescent current. Are there any disadvantages of putting a weak pull resistor on MISO, MOSI and SCLK?

2

Not really any disadvantages, no.

To minimize power consumption you’d likely want to pull them to the state that they idle when driven, though (depends on your SPI configuration); 3.3v through 100k is 33uA so not insignificant, but generally in the noise when the system is actually running.

3

Thanks, Hugo.

4

Do IMP003 pins for flash memory have internal pulls on MISO, MOSI, and SCLK when IMP is sleeping?

5

They don’t, no.

6

I measured MX25L4006E quiescent current. It does not increase when the pins are floating to vcc/2, which is good.