MCIMX31L FREESCALE [Freescale Semiconductor, Inc], MCIMX31L Datasheet - Page 16

• Manufacturer Part Number: MCIMX31L
• Description: Multimedia Applications Processors
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Functional Description and Application Information
2.3.19
The PCMCIA Host Adapter provides the control logic for PCMCIA socket interfaces, and requires some
additional external analog power switching logic and buffering. The PCMCIA host adapter module is fully
compliant with the PCMCIA standard release 2.1 (PC Card -16) and supports one PCMCIA socket. The
adapter supports hot-insertion, card detection and removal, CompactFlash
TrueIDE mode. The PCMCIA maps to common memory space, attribute memory space and I/O space.
Each space can be up to 64Mbyte in size. As part of the EMI complex the PCMCIA shares its pins with
the WEIM, SDRAMC, and NFC.
2.3.20
The PWM has a 16-bit counter and is optimized to generate sounds from stored sample audio images and
it can also generate tones. It uses 16-bit resolution and a 4x16 data FIFO to generate sound. The following
features characterize the PWM. the 16-bit up-counter has a source selectable clock with 4 x 16 FIFO to
minimize interrupt overhead. Clock in frequency is controlled by a12-bit prescaler for division of 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.
2.3.21
The RNGA module is a digital integrated circuit capable of generating 32-bit random numbers. The
RNGA is designed to comply with FIPS-140 standards for randomness and non-determinism. The random
bits are generated by clocking shift registers with clocks derived from ring oscillators. The configuration
of the shift registers ensures statistically good data (that is, data that looks random). The oscillators with
their unknown frequencies provide the required entropy needed to create random data.
It is important to note that there is no known cryptographic proof showing that this is a secure method of
generating random data. In fact, there may be an attack against the random number generator described in
this document if its output is used directly in a cryptographic application (the attack is based on the
linearity of the internal shift registers). Due to lack of a secure method and the potential for attacks,
Freescale Semiconductor recommends that the random data produced by this module be used as an input
seed to a NIST approved (based on DES or SHA-1) or cryptographically secure (RSA Generator or BBS
Generator) random number generation algorithm. It is also recommended that other sources of entropy be
used along with the RNGA to generate the seed to the pseudo-random algorithm. But this is optional. The
more random sources combined to create the seed the better.
The RNGA uses a 32-bit IP Bus slave interface and contains a 16 × 32 FIFO. It provides a Secure mode
or operations as well as a power saving mode
2.3.22
The RTC module maintains the system clock, provides stopwatch, alarm, and interrupt functions, and
supports the following features.
16
•
Full clock—days, hours, minutes, seconds
PCMCIA Host Adapter (PCMCIA)
Pulse-Width Accelerator (PWM)
Random Number Generator Accelerator (RNGA)
Real Time Clock (RTC)
i.MX31/i.MX31L Advance Information, Rev. 1.4
Preliminary
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, and ATA emulation in
Freescale Semiconductor