20-42
MC9328MX1 Reference Manual
MOTOROLA
Multimedia Card/Secure Digital Host Controller Module (MMC/SD)
20.7.3.2 Stream Access—Stream Write and Stream Read (MMC Only)
The module also supports Stream Mode access to the card. In Stream Mode data is transferred in bytes and
no CRC appended at the end of each package/block. So it is relatively more effective. However with CRC,
the user may use either the checking mechanism to verify the content, or the bit content self-independent,
like raw sound track.
20.7.3.2.1 Stream Write
WRITE_DAT_UNTIL_STOP
(CMD20) starts the data transfer from the MMC/SD module to the card,
beginning at the specified address and continuing until the MMC/SD module issues a stop command.
When partial blocks are allowed (CSD parameter WRITE_BL_PARTIAL is set), the data stream can start
and stop at any address within the card address space, otherwise it can only start and stop at block
boundaries. Because the amount of data to be transferred is not determined in advance, a CRC cannot be
used. When the end of the memory range is reached while sending data and no stop command is sent by the
MMC/SD module, any additional data transferred is discarded.
The maximum clock frequency for a stream write operation is given by Equation 20-3 using fields of the
Card-Specific Data Register.
Eqn. 20-3
•
TRAN_SPEED = Maximum Data Transfer Rate
•
READ_BL_LEN = Maximum Read Data Block Length
•
NSAC = Data Read Access Time 2 in CLK Cycles
•
TAAC = Data Read Access Time 1
•
R2W_FACTOR = Write Speed Factor
When the MMC/SD module attempts to use a frequency higher than the value defined in Equation 20-3,
the card may be unable to process the data, causing an overrun condition. When an overrun condition is
detected, the card stops programming, sets the OVERRUN error bit in the Card Status Register, ignores all
further data transfer attempts, and waits in the receive state for a stop command. When the MMC/SD
module tries to write over a write-protected area, the write operation is aborted and the card sets the
WP_VIOLATION bit in the Card Status Register.
Code Example 20-11 on page 20-43 provides the program code for the stream write.
MAXIMUM SPEED
MIN TRAN_SPEED
8 2
WRITE_BL_LEN
•
NSAC
–
TAAC R2W_FACTOR
•
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,
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Summary of Contents for DragonBall MC9328MX1
Page 68: ...1 12 MC9328MX1 Reference Manual MOTOROLA Introduction ...
Page 86: ...2 18 MC9328MX1 Reference Manual MOTOROLA Signal Descriptions and Pin Assignments ...
Page 116: ...3 30 MC9328MX1 Reference Manual MOTOROLA Memory Map ...
Page 126: ...4 10 MC9328MX1 Reference Manual MOTOROLA ARM920T Processor ...
Page 160: ...8 8 MC9328MX1 Reference Manual MOTOROLA System Control ...
Page 272: ...13 32 MC9328MX1 Reference Manual MOTOROLA DMA Controller ...
Page 281: ...Programming Model MOTOROLA Watchdog Timer Module 14 9 ...
Page 282: ...14 10 MC9328MX1 Reference Manual MOTOROLA Watchdog Timer Module ...
Page 300: ...15 18 MC9328MX1 Reference Manual MOTOROLA Analog Signal Processor ASP ...
Page 438: ...18 16 MC9328MX1 Reference Manual MOTOROLA Serial Peripheral Interface Modules SPI 1 and SPI 2 ...
Page 478: ...19 40 MC9328MX1 Reference Manual MOTOROLA LCD Controller ...
Page 574: ...21 32 MC9328MX1 Reference Manual MOTOROLA Memory Stick Host Controller MSHC Module ...
Page 598: ...23 16 MC9328MX1 Reference Manual MOTOROLA Real Time Clock RTC ...
Page 670: ...24 72 MC9328MX1 Reference Manual MOTOROLA SDRAM Memory Controller ...
Page 726: ...25 56 MC9328MX1 Reference Manual MOTOROLA SmartCard Interface Module SIM ...
Page 736: ...26 10 MC9328MX1 Reference Manual MOTOROLA General Purpose Timers ...
Page 854: ...29 18 MC9328MX1 Reference Manual MOTOROLA I2C Module ...
Page 900: ...30 46 MC9328MX1 Reference Manual MOTOROLA Synchronous Serial Interface SSI ...
Page 942: ...32 26 MC9328MX1 Reference Manual MOTOROLA GPIO Module and I O Multiplexer IOMUX ...