OM13005,598 NXP Semiconductors, OM13005,598 Datasheet - Page 15

• Manufacturer Part Number: OM13005,598
• Description: BOARD EVAL EM773 METER US PLUG
• Manufacturer: NXP Semiconductors
• Type: Other Power Managementr

Specifications of OM13005,598

• Design Resources: Plug Meter Schematics, Gerber Files USB Dongle Schematics, Gerber Files
• Main Purpose: Power Management, Energy/Power Meter
• Embedded: Yes, MCU, 32-Bit
• Utilized Ic / Part: EM773FHN33,551
• Interface Type: USB
• Maximum Operating Temperature: + 150 C
• Operating Supply Voltage: 1.8 V to 3.6 V
• Product: Power Management Development Tools
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Primary Attributes: -
• Secondary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: EM773, OL2381
• Other names: 568-6680

NXP Semiconductors
EM773
Objective data sheet
7.15.1.3 Watchdog oscillator
7.15.5.1 Sleep mode
7.15.2 System PLL
7.15.3 Clock output
7.15.4 Wake-up process
7.15.5 Power control
The watchdog oscillator can be used as a clock source that directly drives the CPU, the
watchdog timer, or the CLKOUT pin. The watchdog oscillator nominal frequency is
programmable between 7.8 kHz and 1.7 MHz. The frequency spread over processing and
temperature is ±40 %.
The PLL accepts an input clock frequency in the range of 10 MHz to 25 MHz. The input
frequency is multiplied up to a high frequency with a Current Controlled Oscillator (CCO).
The multiplier can be an integer value from 1 to 32. The CCO operates in the range of
156 MHz to 320 MHz, so there is an additional divider in the loop to keep the CCO within
its frequency range while the PLL is providing the desired output frequency. The output
divider may be set to divide by 2, 4, 8, or 16 to produce the output clock. Since the
minimum output divider value is 2, it is insured that the PLL output has a 50 % duty cycle.
The PLL is turned off and bypassed following a chip reset and may be enabled by
software. The program must configure and activate the PLL, wait for the PLL to lock, and
then connect to the PLL as a clock source. The PLL settling time is 100 μs.
The EM773 features a clock output function that routes the IRC oscillator, the system
oscillator, the watchdog oscillator, or the main clock to an output pin.
The EM773 begins operation at power-up and when awakened from Deep power-down
mode by using the 12 MHz IRC oscillator as the clock source. This allows chip operation
to resume quickly. If the system oscillator or the PLL is needed by the application,
software will need to enable these features and wait for them to stabilize before they are
used as a clock source.
The EM773 supports a variety of power control features. There are three special modes of
processor power reduction: Sleep mode, Deep-sleep mode, and Deep power-down mode.
The CPU clock rate may also be controlled as needed by changing clock sources,
reconfiguring PLL values, and/or altering the CPU clock divider value. This allows a
trade-off of power versus processing speed based on application requirements. In
addition, a register is provided for shutting down the clocks to individual on-chip
peripherals, allowing fine tuning of power consumption by eliminating all dynamic power
use in any peripherals that are not required for the application. Selected peripherals have
their own clock divider which provides even better power control.
When Sleep mode is entered, the clock to the core is stopped. Resumption from the Sleep
mode does not need any special sequence but re-enabling the clock to the ARM core.
In Sleep mode, execution of instructions is suspended until either a reset or interrupt
occurs. Peripheral functions continue operation during Sleep mode and may generate
interrupts to cause the processor to resume execution. Sleep mode eliminates dynamic
power used by the processor itself, memory systems and related controllers, and internal
buses.
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 1 September 2010
Energy metering IC
© NXP B.V. 2010. All rights reserved.
EM773
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