MDK-ARM Keil, MDK-ARM Datasheet - Page 60

• Manufacturer Part Number: MDK-ARM
• Description: KIT REALVIEW MCU DEVELOPMENT
• Manufacturer: Keil
• Type: Compiler and IDEr

Specifications of MDK-ARM

• For Use With/related Products: ARM MCUs
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

60
Chapter 3. RL-Flash Introduction
MultiMedia Cards
The easiest way to add a large amount of low cost data storage to a small
microcontroller system is through a Secure Digital (SD) or Multi Media Card
(MMC). These cards are available in ever increasing densities at ever lower
prices. Although they are available from a wide range of manufacturers, the
cards conform to a standard specification that defines the interface protocol
between the microcontroller and the memory card. The SD and MMC protocols
allow the microcontroller to communicate in a serial SPI mode at 25KBytes/sec
or through a 4-bit-wide bus at 100KBytes/sec. In order to use the memory card
in parallel mode, the microcontroller must have a dedicated Multimedia Card
Interface (MCI) peripheral. If this is the case, a dedicated driver for supported
microcontrollers is provided in
.
C:\KEIL\ARM\RL\FLASHFS\DRIVERS
Simply select the appropriate MCI driver and add this to your project as shown
below:
To configure RL-Flash to use an SD\MM card add the MCI or SPI driver for
your microcontroller and configure
to use the memory card. In
File_Config.c
we must enable the memory card and select it as the default drive. It
File_Config.c
is possible to configure the memory card based file system to use an additional
cache of RAM within the microcontroller. This can be from 1K up to 32KBytes
in size. It is really only necessary to enable this option if you are using a
dedicated MCI peripheral. With the cache enabled, the MCI peripheral is able to
perform multiple sector writes and multiple sector reads. If you are using an SPI
peripheral to communicate with the SD/MMC card, you will not get any
significant performance gains with the cache enabled. The RL-Flash makes use
of the Direct Memory Access (DMA) peripherals within supported
microcontrollers to stream data to and from the SD/MMC card. If the DMA is
limited to certain regions of memory, the “relocate buffer cache” option allows
you to force the file buffer cache into a suitable region. Do check that this is
correct for your particular microcontroller.