Functional Example for the MMC/SD Module
MOTOROLA
Multimedia Card/Secure Digital Host Controller Module (MMC/SD)
20-53
NOTE:
The interrupt period is applicable for both memory and I/O operations. The
definition of the interrupt period for operations with single blocks is
different from the definition for multiple block data transfers.
20.7.7.2 SD I/O Suspend and Resume
Within a multi-function SD I/O or a card with both I/O and memory functions, there are multiple devices
(I/O and memory) that share access to the MMC/SD bus. To share access to the MMC/SD module among
multiple devices, SD I/O and combo cards optionally implement the concept of suspend/resume. When a
card supports suspend/resume, the MMC/SD module can temporarily halt a data transfer operation to one
function or memory (suspend) to free the bus for a higher priority transfer to a different function or
memory. After this higher-priority transfer is complete, the original transfer is resumed (re-started) where
it left off. Support of suspend/resume is optional on a per-card basis.
To perform the suspend/resume operation on the MMC/SD bus, the MMC/SD module performs the
following steps:
1. Determines the function currently using the SD_DAT [3:0] line(s).
2. Requests the lower priority or slower transaction to suspend.
3. Waits for the transaction suspension to complete.
4. Begins the higher priority transaction.
5. Waits for the completion of the higher priority transaction.
6. Restores the suspended transaction.
20.7.7.3 SD I/O ReadWait
The optional ReadWait (RW) operation is defined only for the SD 1-bit and 4-bit modes. The ReadWait
operation allows the MMC/SD module to signal a card that it is reading multiple registers
(
IO_RW_EXTENDED
, CMD53) to temporarily stall the data transfer while allowing the MMC/SD module to
send commands to any function within the SD I/O device. To determine when a card supports the
ReadWait protocol, the MMC/SD module must test capability bits in the card internal registers. The timing
for ReadWait is based on the interrupt period. Code Example 20-13 on page 20-54 provides the
programming code for the SD I/O RW operation.
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 ...