uhs_reg

         UHS-1 Register
      
Module Instance Base Address Register Address
i_sdmmc_sdmmc 0xFF808000 0xFF808074

Offset: 0x74

Access: RW

Bit Fields
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16

ddr_reg

RW 0x0

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

volt_reg

RW 0x0

uhs_reg Fields

Bit Name Description Access Reset
31:16 ddr_reg
DDR mode. These bits indicate DDR mode of operation to the core for the data transfer.
                                                 0  Non-DDR mode
                                                 1  DDR mode
UHS_REG [16] should be set for card number 0, UHS_REG [17] for card number 1 and so on.
Value Description
0 NONDDR
1 DDR
RW 0x0
15:0 volt_reg
High Voltage mode. Determines the voltage fed to the buffers by an
external voltage regulator.
                                                 0  Buffers supplied with 3.3V Vdd
                                                 1  Buffers supplied with 1.8V Vdd
These bits function as the output of the host controller and are fed to an external voltage regulator. The voltage regulator must switch the voltage of the buffers of a particular card to either 3.3V or 1.8V, depending on the
value programmed in the register.
VOLT_REG[0] should be set to 1’b1 for card number 0 in order to make it
operate for 1.8V.
Value Description
0 BUF33V
1 BUF18V
RW 0x0