NXP Semiconductors MC9328MX1, Настройка и использование, Страница: 11 / 14

References
Setup and Use of the Multimedia Card/Secure Digital Host Controller Application Note, Rev. 0
Freescale Semiconductor 11
The setting for the data transfer for both polling and DMA is described under the MMC/SD host
controller chapter which is referenced on [3] for the i.MX1 and [4] for the i.MXL. The frequency ranges
have been tested without any other loads—that is, LCD module or any other modules within the
processor, in use and without using any interrupts. Two things to be aware of during data transfer mode:
polling mode and DMA transfer. Polling mode does not work when using multiple blocks for SD cards.
After writing data, the program holds when checking the FIFO full status. If using SD cards for multiple
blocks transfer, then DMA is the best solution. When using DMA to transfer data the priority is
important. If the DMA is not set to a high priority then data can get lost and cause a hold and wait for data
transfer to complete.
6 References
The following reference documents are used in conjunction with this document for configuration of the
MMC/SD module.
6.1 Freescale Semiconductor Documents
The following i.MX technical reference manuals may be found at the Freescale Semiconductor Inc.
World Wide Web site at http://www.freescale.com/imx. These documents may be downloaded directly
from the World Wide Web site, or printed versions may be ordered.
[1]:
MC9328MX1 Data Sheet
(order number MC9328MX1)
[2]:
MC9328MXL Data Sheet
(order number MC9328MXL)
[3]:
MC9328MX1 Reference Manual
(order number MC9328MX1RM)
SD DMA Single 4 MHz 25 MHz
SD DMA Multiple 4 MHz 25 MHz
Table 4. i.MXL Frequency Range
Card Type Method Size (Block Size) Minimum Maximum
MMC Polling Single 4 MHz 20 MHz
MMC Polling Multiple 4 MHz 20 MHz
MMC DMA Single 4 MHz 20 MHz
MMC DMA Multiple 4 MHz 20 MHz
SD (1 Bit Mode) Polling Single 4 MHz 20 MHz
SD (4 Bit Mode) Polling Single 8 MHz 20 MHz
SD Polling Multiple – –
SD DMA Single 4 MHz 20 MHz
SD DMA Multiple 4 MHz 20 MHz
Table 3. i.MX1 Frequency Range (continued)
Card Type Method Size (Block Size) Minimum Maximum