PXA250 INTEL [Intel Corporation], PXA250 Datasheet - Page 35

• Manufacturer Part Number: PXA250
• Description: Intel-R PXA250 and PXA210 Applications Processors
• Manufacturer: INTEL [Intel Corporation]

4.6
4.6.1
Datasheet
Reset and Power AC Timing Specifications
The applications processor asserts the nRESET_OUT pin in one of several different modes:
The following sections give the timing and specifications for the entry and exit of these modes.
Power On Timing
The External Voltage Regulator and other power-on devices must provide the applications
processor with a specific sequence of power and resets to ensure proper operation. This sequence is
shown in Figure 4, “Power-On Reset Timing” on page 36, and detailed in Table 13, “Power-On
Timing Specifications” on page 36.
On the applications processor, it is important that the power supplies be powered-up in a certain
order to avoid high current situations. The required order is:
The supply in step 3 may be powered at the same time as those in step 2, however, VCCN should
not be powered before VCCQ.
1. BATT_VCC
2. VCCQ
3. VCCN
4. VCC and PLL_VCC
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Power On
Hardware Reset
Watchdog Reset
GPIO Reset
Sleep Mode
Electrical, Mechanical, and Thermal Specification — PXA250 and PXA210
35