Figure 3-22. Power-Up Timing Regulators - Motorola APX 1000 Detailed Service Manual

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Theory of Operation

: Controller

3.2.2.1.4 Power-up Timing

The powering up of the radio starts with the MAKO. Once the radio knob is pressed to 'ON' and

battery voltage is supplied, a pass FET is activated to deliver battery voltage to MAKO and external

regulators. The external 3.6 V is first turned on then MAKO activates its 24.576 MHz clock, and the

remaining regulators begin to turn on. Once all the regulators have turned on, MAKO releases its

reset. The CPLD is then powered on from the 1.875 V external regulator and takes MAKO 24.576

MHz clock and divides it to 32.768 kHz in order to provide for OMAP. OMAP starts to power up upon

receiving voltages 1.4 V, 1.85 V, and the 32.768 kHz clock. OMAP than activates it 12 MHz clock and

releases its reset. It then starts to run the boot loader stored in flash. A more detailed timing view of

the regulators is shown in

sw1_boost_slimit

sw2_softstart[0]

sw2_softstart[1]

sw2_softstart[2]

41.6us(1024clk24)

Figure 3-22. Power-up Timing Regulators

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