Zynq UltraScale+ Devices Register Reference > Module Summary > SDIO Module > reg_sdmasysaddrlo (SDIO) Register

reg_sdmasysaddrlo (SDIO) Register

reg_sdmasysaddrlo (SDIO) Register Description

Register Namereg_sdmasysaddrlo
Relative Address0x0000000000
Absolute Address 0x00FF160000 (SD0)
0x00FF170000 (SD1)
Width16
TyperwNormal read/write
Reset Value0x00000000
DescriptionDual purpose: low SDMA address, Auto CMD23 arg.

Contains the Lower 16 bits for: * SDMA transfer memory address, or * Second argument for the Auto CMD23. (1) SDMA System Address: System memory address for an SDMA transfer. When the SDIO Controller stops an SDMA transfer, this register points to the system address of the next contiguous data position. It can be accessed only if no transaction is executing (i.e., after a transaction has stopped). Read operations during transfers may return an invalid value. The Host Driver shall initialize this register before starting an SDMA transaction. After SDMA has stopped, the next system address of the next contiguous data position can be read from this register. The SDMA transfer waits at every boundary specified by the Host SDMA Buffer Boundary in the Block Size register. The SDIO Controller generates a DMA Interrupt to request the Host Driver to update this register. The Host Driver sets the next system address of the next data position to this register. When the most upper byte of this register (003h) is written, the SDIO Controller restarts the SDMA transfer.When restarting SDMA by the Resume command or by setting [Continue Request] in the Block Gap Control register, the SDIO Controller restarts at the next contiguous address stored in the SDMA System Address register. ADMA does not use this register. (2) Second Argument for Auto CMD23: This register is used with the Auto CMD23 to set a 32-bit block count value to the argument of the CMD23 while executing Auto CMD23. If Auto CMD23 is used with ADMA, the full 32-bit block count value can be used. If Auto CMD23 is used without AMDA, the available block count value is limited by the Block Count register. 65535 blocks is the maximum value in this case.

reg_sdmasysaddrlo (SDIO) Register Bit-Field Summary

Field NameBitsTypeReset ValueDescription
sdma_sysaddress15:0rwNormal read/write0x0System memory byte address [15:0], or
AutoCMD23 command argument [15:0].