CC1120: What is the pin state for CS_N and RESET_N in sleep mode.

Juan Sebastian cabrera

Part Number: CC1120

Dear E2E community

I'm wondering what is the pin state for CS_N and RESET_N in sleep mode? Do it have pull-up resistors built in? What happens if the microcontroller, to reduce power consumption, turns off its internal pull-up resistor? Does the radio keep the sleep state? Is it necessary to connect external pull-ups if the microcontroller disables its internal ones?

over 4 years ago

0 TER over 4 years ago

TI__Guru**** 317180 points

CS_N and RESET_N are digital inputs without pull-up. These pins has to be defined externally.

Dependent on the MCU: Some retain their pin status even in sleep meaning that the pin could be set to be defined without a pull-up from the MCU side.

0 Juan Sebastian cabrera over 4 years ago in reply to TER

Prodigy 45 points

Thanks for your answer. Where can I find this information? I mean, what document or datasheet is specified?

Thanks again.

0 TER over 4 years ago in reply to Juan Sebastian cabrera

TI__Guru**** 317180 points

Based on what is not stated in the documentation. If pull-up (or similar) was used, this would have been documented.

0 Juan Sebastian cabrera over 4 years ago in reply to TER

Prodigy 45 points

First of all, thanks for your answer. However I can't understand your answer probably because my question was wrong. So my question is where can I see a diagram or documented information about my concern? I need to record this information in my project documentation.

My concern is if the CC1120 radio requires external pull-ups to maintain the HIGH level while the microcontroller is in sleep mode. My problem is that my current uC disables its internal pull-up during this stage, so I think I need to connect external pull-ups to keep the level HIGH on these pins.

Thanks for your support.

0 TER over 4 years ago in reply to Juan Sebastian cabrera

TI__Guru**** 317180 points

Which MCU do you use?

Sub-1 GHz

Sub-1 GHz forum

CC1120: What is the pin state for CS_N and RESET_N in sleep mode.