Configuration of default voltage level for dual-voltage input/output pad cell via voltage rail ramp up timing

1. A method comprising:

monitoring, at an integrated circuit (IC) package of an electronic device, a first voltage rail and a second voltage rail of the electronic device; and

configuring a first set of one or more input/output (IO) pad cells of the IC package to operate at one of a non-zero first voltage level or a non-zero second voltage level depending on which of the first voltage rail and the second voltage rail ramps up to its respective specified operational voltage level first;

wherein configuring the first set of one or more IO pad cells comprises:

responsive to the first voltage rail ramping up to the first voltage level before the second voltage rail has ramped up to the second voltage level, configuring the first set of one or more IO pad cells to operate at the first voltage level; and

responsive to the second voltage rail ramping up to the second voltage level before the first voltage rail has ramped up to the first voltage level, configuring the first set of one or more IO pad cells to operate at the second voltage level;

wherein the first voltage level is different from the second voltage level.

2. The method of claim 1 , further comprising:

configuring the first set of one or more IO pad cells to operate at a select one of the first voltage level and the second voltage level as specified by a configuration register responsive to the first voltage rail ramping up to the first voltage level at the same time that the second voltage rail ramps up to the second voltage level.

3. The method of claim 1 , wherein:

monitoring the first voltage rail and the second voltage rail comprises monitoring the first voltage rail and the second voltage rail in response to a power cycling of the electronic device.

4. The method of claim 3 , further comprising:

executing a boot process at a processor of the IC package responsive to the power cycling; and

reconfiguring the first set of one or more IO pad cells to operate at one of the first voltage level or the second voltage level as part of the boot process.

5. The method of claim 1 , further comprising:

subsequent to configuring the first set of one or more IO pad cells, executing a set of executable instructions at a processor of the IC package, the set of executable instructions to manipulate the processor to reconfigure the first set of one or more IO pad cells to operate at the other of the first voltage level or the second voltage level.

6. The method of claim 1 , further comprising:

monitoring, at the IC package, a third voltage rail and a fourth voltage rail of the electronic device; and

configuring a second set of one or more IO pad cells of the IC package to operate at one of a non-zero third voltage level or a non-zero fourth voltage level depending on which of the third voltage rail and the fourth voltage rail ramps up to its respective specified operational voltage level first.

7. An apparatus comprising:

an integrated circuit (IC) package comprising:

a first voltage rail;

a second voltage rail;

a first set of one or more input/output (IO) pad cells; and

a power sequence detector coupled to the first and second voltage rails, the power sequence detector to monitor the first and second voltage rails and configure the first set of one or more IO pad cells to operate at one of a non-zero first voltage level or a non-zero second voltage level depending on which of the first voltage rail and the second voltage rail ramps up to its respective specified operational voltage level first;

wherein the power sequence detector is to:

configure the first set of one or more IO pad cells to operate at the first voltage level responsive to the first voltage rail ramping up to the first voltage level before the second voltage rail has ramped up to the second voltage level; and

configure the first set of one or more IO pad cells to operate at the second voltage level responsive to the second voltage rail ramping up to the second voltage level before the first voltage rail has ramped up to the first voltage level;

wherein the first voltage level is different from the second voltage level.

8. The apparatus of claim 7 , wherein the power sequence detector further is to:

configure the first set of one or more IO pad cells to operate at the first voltage level responsive to the first voltage rail ramping up to the first voltage level at the same time that the second voltage rail ramps up to the second voltage level, wherein the first voltage level is greater than the second voltage level.

9. The apparatus of claim 7 , wherein the power sequence detector comprises:

a first voltage level sensor having an input coupled to the first voltage rail, an input to receive a clock signal, and an output that is asserted when a voltage level on the first voltage rail reaches the first voltage level;

a second voltage level sensor having an input coupled to the second voltage rail, an input to receive the clock signal, and an output that is asserted when a voltage level on the first voltage rail reaches the first voltage level;

a first latch having an input coupled to the output of the first voltage rail, an input to receive the clock signal, and an output;

a second latch having an input coupled to the output of the second voltage rail, an input to receive the clock signal, and an output; and

sequence detect logic having an input coupled to the output of the first latch, an input coupled to the output of the second latch, and an output to provide one of a first value or a second value depending on which output of the first and second latches is asserted first, wherein the first value represents the first voltage level and the second value represents the second voltage level.

10. The apparatus of claim 7 , wherein:

the power sequence detector is to monitor the first voltage rail and the second voltage rail in response to a power cycling of the IC package.

11. The apparatus of claim 10 , wherein the IC package further comprises:

a processor to execute a boot process responsive to the power cycling, wherein the boot process is to manipulate the processor to reconfigure the first set of one or more IO pad cells to operate at one of the first voltage level or the second voltage level.

12. The apparatus of claim 7 , wherein the IC package further comprises:

a processor to execute a set of executable instructions subsequent to configuring the first set of one or more IO pad cells, the set of executable instructions to manipulate the processor to reconfigure the first set of one or more IO pad cells to operate at the other of the first voltage level or the second voltage level.

13. The apparatus of claim 7 , wherein:

the IC package further comprises a second set of one or more IO pad cells; and

the power sequence detector further is to monitor a third voltage rail and a fourth voltage rail, and to configure the second set of one or more IO pad cells to operate at one of a non-zero third voltage level or a non-zero fourth voltage level depending on which of the third voltage rail and the fourth voltage rail ramps up to its respective specified operational voltage level first.

14. The apparatus of claim 7 , further comprising:

a power management component external to the IC package, the power management component to control a timing of a voltage ramp up of the first and second voltage rails to configure a default voltage level for the first set of one or more IO pad cells.

15. The apparatus of claim 14 , further comprising:

a storage element coupled to the power management component, the storage element storing timing settings representing the timing of the voltage ramp up of the first and second voltage rails.

16. The apparatus of claim 7 , wherein:

the first set of one or more IO pad cells comprises a set of one or more general purpose IO (GPIO) pad cells.

17. A method comprising:

providing an electronic device comprising a power management component powering first and second voltage rails and an integrated circuit (IC) package having a set of one or more input/output (IO) pad cells configurable to be powered by either a non-zero operational first voltage level provided by the first voltage rail or a non-zero operational second voltage level provided by the second voltage rail; and

configuring the set of one or more IO pad cells to be powered by the first voltage level by ramping up the first voltage rail to the first voltage level prior to ramping up the second voltage rail to the second voltage level, wherein the first voltage level is different from the second voltage level.

18. The method of claim 17 , wherein:

configuring the set of one or more IO pad cells comprises configuring the set of one or more IO pad cells responsive to a power cycling of the IC package.