![GigaDevice Semiconductor GD32F10 Series Скачать руководство пользователя страница 524](http://html.mh-extra.com/html/gigadevice-semiconductor/gd32f10-series/gd32f10-series_user-manual_2225800524.webp)
GD32F10x User Manual
524
receive or transmit data, the host will stop the SDIO_CLK and freeze SDIO state machines to
avoid the corresponded error. Only state machines are frozen, the AHB interface is still alive.
So, the FIFO can access by AHB bus.
Command unit
The command unit implements command transfer to the card
.
The data transfer flow is
controlled by Command State Machine (CSM). After a write operation to SDIO_CMDCTL
register and CSMEN in SDIO_CMDCTL register is 1, the command transfer starts. It firstly
sends a command to the card. The command contains 48 bits send by SDIO_CMD signal
which sends 1 bit to card at one SDIO_CLK. The 48 bits command contains 1 bit Start bit, 1
bit Transmission bit, 6 bits command index defined by CMDIDX bits in SDIO_CMDCTL
register, 32 bits argument defined in SDIO_CMDAGMT register, 7 bits CRC, and 1 bit end bit.
Then receive response from the card if CMDRESP in SDIO_CMDCTL register is not
0b00/0b10. There is short response which have 48 bits or long response which have 136 bits.
The response stores in SDIO_RESP0 - SDIO_RESP3 registers. The command unit also
generates the command status flags defined in SDIO_STAT register.
Command state machine
CS_Idle
After reset, ready to send command.
1.CSM enabled and WAITDEND enabled
→
CS_Pend
2.CSM enabled and WAITDEND disabled
→
CS_Send
3.CSM disabled
→
CS_Idle
Note:
The state machine remains in the Idle state for at least eight SDIO_CLK periods to meet
the N
CC
and N
RC
timing constraints. N
CC
is the minimum delay between two host commands, and
N
RC
is the minimum delay between the host command and the response.
CS_Pend
Waits for the end of data transfer.
1.The data transfer complete
→
CS_Send
2.CSM disabled
→
CS_Idle
CS_Send
Sending the command.
1.The command transmitted has response
→
CS_Wait
2.The command transmitted doesn’t have response
→
CS_Idle
3.CSM disabled
→
CS_Idle
CS_Wait
Wait for the start bit of the response.
1.Receive the response(detected the start bit)
→
CS_Receive
2.Timeout is reached without receiving the response
→
CS_Idle
3.CSM disabled
→
CS_Idle
Note:
The command timeout has a fixed value of 64 SDIO_CLK clock periods.
Содержание GD32F10 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F10x Arm Cortex M3 32 bit MCU User Manual Revision 2 6 Jun 2022 ...
Страница 63: ...GD32F10x User Manual 63 programmed during the chip production ...
Страница 117: ...GD32F10x User Manual 117 010 1 0 011 0 9 ...
Страница 416: ...GD32F10x User Manual 416 shadow register updates every update event ...
Страница 427: ...GD32F10x User Manual 427 value ...
Страница 518: ...GD32F10x User Manual 518 These bits are not used in SPI mode ...