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I.MX27 View Datasheet(PDF) - Freescale Semiconductor

Part Name
Description
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I.MX27
Freescale
Freescale Semiconductor Freescale
I.MX27 Datasheet PDF : 152 Pages
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Functional Description and Application Information
2.3.25 Personal Computer Memory Card International Association
(PCMCIA)
The Personal Computer Memory Card International Association (PCMCIA) provides the PCMCIA 2.1
standard, which defines the usage of memory and I/O devices as insertable and exchangeable peripherals
for personal computers or PDAs. Examples of these types of devices include CompactFlash and WLAN
adapters.
The pcmcia_if host adapter module provides the control logic for PCMCIA socket interfaces, and requires
some additional external analog power switching logic and buffering. The additional external buffers
allow the pcmcia_if host adapter module to support one PCMCIA socket. The pcmcia_if shares its chip
level I/O with the external interface to memory (EIM) pins. Additional logic is required to multiplex the
EIM and the pcmcia_if on the same pins.
2.3.26 Digital Phase Lock Loop (DPLL)
Two on-chip Digital Phase Lock Loop (DPLLs) provide clock generation in digital and mixed
analog/digital chips designed for wireless communication and other applications. The DPLLs produce a
high-frequency chip clock signals with a low frequency and phase jitter.
2.3.27 Pulse-Width Modulator (PWM)
The Pulse-Width Modulator (PWM) has a 16-bit counter and is optimized to generate sounds from stored
sample audio images; it can also generate tones. The PWM uses 16-bit resolution and a 4 × 16 data FIFO
to generate sound. The 16-bit up-counter has a source selectable clock with 4 × 16 FIFO to minimize
interrupt overhead. Clock-in frequency is controlled by a 12-bit prescaler for the division of a clock.
Capable of sound and melody generation, the PWM has an active-high or active-low configurable output,
and can be programmed to be active in low-power and debug modes. The PWM can be programmed to
generate interrupts at compare and rollover events.
2.3.28 Real Time Clock (RTC)
The Real Time Clock (RTC) module maintains the system clock, provides stopwatch, alarm, and
interrupt functions, and supports the following features:
• Full clock—days, hours, minutes, seconds
• Minute countdown timer with interrupt
• Programmable daily alarm with interrupt
• Sampling timer with interrupt
• Once-per-day, once-per-hour, once-per-minute, and once-per-second interrupts
• Operation at 32.768 kHz or 32 kHz, or 38.4 kHz (determined by reference clock crystal)
The prescaler converts the incoming crystal reference clock to a 1 Hz signal, which is used to increment
the seconds, minutes, hours, and days TOD counters. The alarm functions, when enabled, generate RTC
interrupts when the TOD settings reach programmed values. The sampling timer generates
fixed-frequency interrupts, and the minute stopwatch allows for efficient interrupts on very small
boundaries.
i.MX27 and i.MX27L Data Sheet, Rev. 1.8
20
Freescale Semiconductor
 

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