Voltage Range Specifications for MAGPIO, SIM Interface, nRESET, ENABLE and SWD Interface

[ShaunR]

Hello,

I have been looking through Nordic's documentation for the nRF9160 and trying to find voltage ranges for several pins but am having no luck. Can someone please answer the following questions:

What are the VIH and VIL ranges for the following input pins:

nRESET, ENABLE, SWDCLK

What are the VOH and VOL ranges for the following output pins:

SIM_RST, SIM_CLK

What are the VIH, VIL, VOH, and VOL ranges for the following bidirectional pins:

MAGPIO(2-0), SWDIO, SIM_IO

Thanks for your time!

[Amanda Hsieh]

Hi Shaun, 

The ENABLE pin is connected to VDD. Please see the Operating conditions

The Reset pin has an always-on internal pull-up resistor connected to nRF9160 internal voltage typically of 2.2 V level. The value of the pull-up resistor is given in Pin reset.

The SWDCLK is Digital input and SIM_RST, SIM_CLK, SWDIO, and SIM_IO are Digital I/O.  Please see the GPIO Electrical specification.

The MAGPIO, please see the Operating conditions

All pins that are purely controlled by the application controller is referenced to VDD_GPIO, while pins controlled by the modem are described in the operating conditions.

-Amanda H.

[ShaunR]

Hi Amanda,

Thanks for the response to my questions!

Sounds good about the SWD pins, but I am still wondering about the rest of the pins I mentioned and their VIL, VIH, VOL and VOH ranges. In my experience, most cellular module manufacturers document these ranges when applicable for each pin on the module, but I still can't find this for the following pins on the nRF9160:

ENABLE

• I understand that this pin needs to be pulled up to VDD to power on the modem.
• However, what is the minimum voltage that must be applied to this pin to start the module? As in: VIHmin = VDD - 0.3V, or something like that.

nRESET

• I understand that this pin is pulled up to 2.2V and should be driven low with an open-drain output to initiate reset.
• However, what is the VILmax for this pin? As in: VILmax = VSS + 0.3V, or something like that.
• Also, what is the maximum voltage that can be applied to this pin before something gets damaged? I understand this pin should not be driven to anything other than VSS, but this information is still good to have documented.

SIM_IO, SIM_CLK, SIM_RST

• I was able to find the VIL, VIH, VOL, and VOH for these pins in this specification: ISO/IEC 7816-3, which was mentioned on the "SIM card interface" page.
• For reference, here are the ranges I found in the ISO/IEC 7816-3 specification: VOL, VIL: 0V to 0.15*VCC_SIM and VOH, VIH: 0.7 * VCC_SIM to VCC_SIM
• I assume the values that I found in that specification are valid for the nRF9160?

MAGPIO Pins

• I see there is a VOH range listed on the "Operating conditions" page, but no VOL range. Is the VOL range documented?
• Also, are these pins just digital outputs, or are they also inputs? The "Pin assignments" page says these pins have a description of "1.8 V general purpose I/O", but the AT command to interface with these pins seems to only let you use them as digital outputs. Can you clarify this please?
• If these pins are bidirectional, then I'd like to also know the VIL and VIH ranges if that information is documented.

Thanks very much for your help!

Best Regards,

ShaunR

[Amanda Hsieh]

I am asking the internal and will be back soon. 

-Amanda H.