cmd
Command Register
| Module Instance | Base Address | Register Address |
|---|---|---|
| i_sdmmc_sdmmc | 0xFF808000 | 0xFF80802C |
Offset: 0x2C
Access: RW
Important: The value of a reserved bit must be maintained in software. When you modify registers containing reserved bit fields, you must use a read-modify-write operation to preserve state and prevent indeterminate system behavior.
| Bit Fields | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 |
start_cmd RW 0x0 |
Reserved |
use_hold_reg RW 0x1 |
volt_switch RW 0x0 |
boot_mode RW 0x0 |
disable_boot RW 0x0 |
expect_boot_ack RW 0x0 |
enable_boot RW 0x0 |
ccs_expected RW 0x0 |
read_ceata_device RW 0x0 |
update_clock_registers_only RW 0x0 |
card_number RW 0x0 |
||||
| 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
send_initialization RW 0x0 |
stop_abort_cmd RW 0x0 |
wait_prvdata_complete RW 0x0 |
send_auto_stop RW 0x0 |
transfer_mode RW 0x0 |
read_write RW 0x0 |
data_expected RW 0x0 |
check_response_crc RW 0x0 |
response_length RW 0x0 |
response_expect RW 0x0 |
cmd_index RW 0x0 |
|||||
cmd Fields
| Bit | Name | Description | Access | Reset | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 31 | start_cmd | Start command. Once command is taken by CIU, bit is cleared. When bit is set, host should not attempt to write to any command registers. If write is attempted, hardware lock error is set in raw interrupt register. Once command is sent and response is received from SD_MMC_CEATA cards, Command Done bit is set in raw interrupt register.
|
RW | 0x0 | ||||||
| 29 | use_hold_reg | Use Hold Register
0 - CMD and DATA sent to card bypassing HOLD Register
1 - CMD and DATA sent to card through the HOLD Register
|
RW | 0x1 | ||||||
| 28 | volt_switch | Voltage switch bit
0 - No voltage switching
1 - Voltage switching enabled; must be set for CMD11 only
|
RW | 0x0 | ||||||
| 27 | boot_mode | Boot Mode
0 - Mandatory Boot operation
1 - Alternate Boot operation
|
RW | 0x0 | ||||||
| 26 | disable_boot | Disable Boot. When software sets this bit along with start_cmd, CIU terminates the boot operation. Do NOT set disable_boot and enable_boot together.
|
RW | 0x0 | ||||||
| 25 | expect_boot_ack | Expect Boot Acknowledge. When Software sets this bit along with enable_boot, CIU expects a boot acknowledge start pattern of 0-1-0 from the selected card.
|
RW | 0x0 | ||||||
| 24 | enable_boot | Enable Bootthis bit should be set only for mandatory boot mode. When Software sets this bit along with start_cmd, CIU starts the boot sequence for the corresponding card by asserting the CMD line low. Do NOT set disable_boot and enable_boot together.
|
RW | 0x0 | ||||||
| 23 | ccs_expected | 0-Interrupts are not enabled in CE-ATA device (nIEN = 1 in
ATA control register), or command does not expect CCS
from device
1-Interrupts are enabled in CE-ATA device (nIEN = 0), and RW_BLK
command expects command completion signal from CE-ATA device
If the command expects Command Completion Signal (CCS) from the CE-ATA device, the software should set this control bit.DWC_mobile_storage sets Data Transfer Over (DTO) bit in RINTSTS register and generates interrupt to host if Data Transfer Over interrupt is not masked.
|
RW | 0x0 | ||||||
| 22 | read_ceata_device | 0-Host is not performing read access (RW_REG or RW_BLK)
towards CE-ATA device
1-Host is performing read access (RW_REG or RW_BLK)
towards CE-ATA device
Software should set this bit to indicate that CE-ATA device is being accessed for read transfer. This bit is used to disable read data timeout indication while performing CE-ATA read transfers.Maximum value of I/O transmission delay can be no less than 10 seconds. DWC_mobile_storage should not indicate read data timeout while waiting for data from CE-ATA device.
|
RW | 0x0 | ||||||
| 21 | update_clock_registers_only | 0-Normal command sequence
1-Do not send commands, just update clock register value into
card clock domain
Following register values transferred into card clock domain: CLKDIV, CLRSRC, CLKENA. Changes card clocks (change frequency, truncate off or on, and set low-frequency mode); provided in order to change clock frequency or stop clock without having to send command to cards.During normal command sequence, when update_clock_registers_only = 0, following control registers are transferred from BIU to CIU: CMD, CMDARG, TMOUT, CTYPE,BLKSIZ, BYTCNT. CIU uses new register values for new command sequence to card(s).When bit is set, there are no Command Done interrupts because no
command is sent to SD_MMC_CEATA cards.
|
RW | 0x0 | ||||||
| 20:16 | card_number | Card number in use. Represents physical slot number of card being accessed. In MMC-Ver3.3-only mode, up to 30 cards are supported; in SD-only mode, up to 16 cards are supported. Registered version of this is reflected on dw_dma_card_num and ge_dma_card_num ports, which can be used to create separate DMA requests, if needed. In addition, in SD mode this is used to mux or demux signals from selected card because each card is interfaced to DWC_mobile_storage by separate bus. |
RW | 0x0 | ||||||
| 15 | send_initialization | 0-Do not send initialization sequence (80 clocks of 1) before
sending this command
1-Send initialization sequence before sending this command
After power on, 80 clocks must be sent to card for initialization before sending any commands to card. Bit should be set while sending first command to card so that controller will initialize clocks before sending command to card. This bit should not be set for either of the boot modes (alternate or mandatory).
|
RW | 0x0 | ||||||
| 14 | stop_abort_cmd | 0-Neither stop nor abort command to stop current data transfer
in progress. If abort is sent to function-number currently
selected or not in data-transfer mode, then bit should be set
to 0.
1-Stop or abort command intended to stop current data transfer
in progress.
When open-ended or predefined data transfer is in progress, and host issues stop or abort command to stop data transfer, bit should be set so that command/data state-machines of CIU can return correctly to idle state. This is also applicable for Boot mode transfers. To Abort boot mode, this bit should be set along with CMD[26] = disable_boot.
|
RW | 0x0 | ||||||
| 13 | wait_prvdata_complete | 0-Send command at once, even if previous data transfer has not
completed
1-Wait for previous data transfer completion before sending
command
The wait_prvdata_complete = 0 option typically used to query status of card during data transfer or to stop current data transfer;card_number should be same as in previous command.
|
RW | 0x0 | ||||||
| 12 | send_auto_stop | 0-No stop command sent at end of data transfer
1-Send stop command at end of data transfer
When set, DWC_mobile_storage sends stop command to SD_MMC_CEATA cards at end of data transfer.
* when send_auto_stop bit should be set, since some data
transfers do not need explicit stop commands
* open-ended transfers that software should explicitly send to
stop command
Additionally, when “resume” is sent to resume suspended memory access of SD-Combo card bit should be set correctly if suspended data transfer needs send_auto_stop.Don't care if no data expected from card.
|
RW | 0x0 | ||||||
| 11 | transfer_mode | 0-Block data transfer command
1-Stream data transfer command
Don’t care if no data expected.
|
RW | 0x0 | ||||||
| 10 | read_write | 0-Read from card
1-Write to card
Don’t care if no data expected from card.
|
RW | 0x0 | ||||||
| 9 | data_expected | 0-No data transfer expected (read/write)
1-Data transfer expected (read/write)
|
RW | 0x0 | ||||||
| 8 | check_response_crc | 0-Do not check response CRC
1-Check response CRC
Some of command responses do not return valid CRC bits. Software should disable CRC checks for those commands in order to disable CRC checking by controller.
|
RW | 0x0 | ||||||
| 7 | response_length | 0-Short response expected from card
1-Long response expected from card
|
RW | 0x0 | ||||||
| 6 | response_expect | 0-No response expected from card
1-Response expected from card
|
RW | 0x0 | ||||||
| 5:0 | cmd_index | Command index |
RW | 0x0 |