![GigaDevice Semiconductor GD32F20 Series Скачать руководство пользователя страница 620](http://html.mh-extra.com/html/gigadevice-semiconductor/gd32f20-series/gd32f20-series_user-manual_2225801620.webp)
GD32F20x User Manual
620
24.4.
SDIO function overview
The following figure shows the SDIO structure. There have two main parts:
The SDIO adapter block consists of control unit which manage clock, command unit
which manage command transfer, data unit which manage data transfer.
The AHB interface block contains access registers by AHB bus, contains FIFO unit which
is data FIFO used for data transfer, and generating interrupt and DMA request signals.
Figure 24-6. SDIO block diagram
SDIO controller
HCLK
SDIO CLK
SDIO_CMD
SDIO_CLK
SDIO_DAT[7:0]
SDIO adapter
control unit
comm and
unit
data uni t
regi sters
FIFO
AHB interface
interrupt
DMA r equest
AHB bus
24.4.1.
SDIO adapter
The SDIO adapter contains control unit, command unit and data unit, and generates signals
to cards. The signals are descript bellow:
SDIO_CLK
: The SDIO_CLK is the clock provided to the card. Each cycle of this signal directs
a one bit transfer on the command line (SDIO_CMD) and on all the data lines (SDIO_DAT).
The SDIO_CLK frequency can vary between 0 MHz and 20 MHz for a Multimedia Card V3.31,
between 0 and 48 MHz for a Multimedia Card V4.2, or between 0 and 25 MHz for an SD/SD
I/O card.
The SDIO uses two clock signals: SDIO adapter clock (SDIOCLK = HCLK) and AHB bus
clock (HCLK)
SDIO_CMD
: This signal is a bidirectional command channel used for card initialization and
transfer of commands. Commands are sent from the SDIO controller to the card and
responses are sent from the card to the host. The CMD signal has two operation modes:
open-drain for initialization (only for MMC3.31 or previous), and push-pull for command
transfer (SD/SD I/O card MMC4.2 use push-pull drivers also for initialization).
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Страница 385: ...GD32F20x User Manual 385 ...
Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...