MEC1322 Datasheet, PDF (286/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
25.5 Signal Description
TABLE 25-1: SIGNAL DESCRIPTION TABLE
Name
Direction
Description
PWM_OUTPUT
OUTPUT Pulse Width Modulated signal to PWMx pin.
25.6 Host Interface
The registers defined for the PWM Interface are accessible by the various hosts as indicated in Section 25.11, "EC-Only
Registers".
25.7 Power, Clocks and Reset
This section defines the Power, Clock, and Reset parameters of the block.
25.7.1 POWER DOMAINS
TABLE 25-2: POWER SOURCES
Name
VCC1
25.7.2 CLOCK INPUTS
Description
The PWM logic and registers are powered by this single power source.
TABLE 25-3: CLOCK INPUTS
Name
100kHz_Clk
48 MHz Ring Oscillator
25.7.3 RESETS
Description
100kHz_Clk clock input for generating low PWM frequencies, such as 10
Hz to 100 Hz.
48 MHz Ring Oscillator clock input for generating high PWM frequencies,
such as 15 kHz to 30 kHz.
TABLE 25-4: RESET SIGNALS
Name
VCC1_RESET
Description
This reset signal resets all the logic in this block to its initial state
including the registers, which are set to their defined default state.
25.8 Interrupts
The PWM block does not generate any interrupt events.
25.9 Low Power Modes
The PWM may be put into a low power state by the chip’s Power, Clocks, and Reset (PCR) circuitry. When the PWM is
in the sleep state, the internal counters reset to 0 and the internal state of the PWM and the PWM_OUTPUT signal set
to the OFF state.
25.10 Description
The PWM_OUTPUT signal is used to generate a duty cycle of specified frequency. This block can be programmed so
that the PWM signal toggles the PWM_OUTPUT, holds it high, or holds it low. When the PWM is configured to toggle,
the PWM_OUTPUT alternates from high to low at the rate specified in the PWMx Counter ON Time Register and PWMx
Counter OFF Time Register.
The following diagram illustrates how the clock inputs and registers are routed to the PWM Duty Cycle & Frequency
Control logic to generate the PWM output.
DS00001719D-page 286
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