GD32W51x User Manual
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23.
Secure digital input/output interface (SDIO)
23.1.
Introduction
The secure digital input/output interface (SDIO) defines the SD/SD I/O /MMC CE-ATA card
host interface, which provides command/data transfer between the APB2 system bus and SD
memory cards, SD I/O cards, Multimedia Card (MMC), and CE-ATA devices.
The supported SD memory card and SD I/O card system specifications are defined in the SD
card Association website at
.
The supported Multimedia Card system specifications are defined through the Multimedia
Card Association website at
, published by the JEDEC SOLID STATE
TECHNOLOGY ASSOCIATION.
The supported CE-ATA system specifications are defined through the CE-ATA workgroup
website at
.
23.2.
Main features
The SDIO features include the following:
MMC:
Full support for Multimedia Card System Specification Version 4.2(and previous
versions) Card and three different data bus modes: 1-bit (default), 4-bit and 8-bit
SD Card:
Full support for
SD Memory Card Specifications Version 2.0
SD I/O:
Full support for
SD I/O Card Specification Version 2.0
card and two different data
bus modes: 1-bit (default) and 4-bit
CE-ATA:
Full compliance with
CE-ATA digital protocol Version 1.1
48MHz data transfer frequency and 8-bit data transfer mode.
Interrupt and DMA request to processor.
Completion Signal enables and disable feature (CE-ATA).
Note:
SDIO supports only one SD, SD I/O, MMC4.2 card or CE-ATA device at any one time
and a stack of MMC4.1 or previous.
23.3.
SDIO bus topology
After a power-on reset, the host must initialize the card by a special message-based bus
protocol.
Each message is represented by one of the following tokens:
Command
: a command is a token which starts an operation. A command is sent from the
host to a card. A command is transferred serially on the CMD line.