Multimedia Card Registers
18.5.1.7 SD_SDMASA Register (offset = 200h) [reset = 0h]
SD_SDMASA is shown in
and described in
This register is used to program a mmc counter to delay command transfers after activating the PAD
power. This value depends on PAD characteristics and voltage.
Figure 18-43. SD_SDMASA Register
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SDMA_SYSADDR
R-0h
LEGEND: R/W = Read/Write; R = Read only; W1toCl = Write 1 to clear bit; -n = value after reset
Table 18-26. SD_SDMASA Register Field Descriptions
Bit
Field
Type
Reset
Description
31-0
SDMA_SYSADDR
R
0h
This register contains the system memory address for a SDMA
transfer.
When the Host Controller stops a SDMA transfer, this register shall
point 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 a 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 the every boundary specified by the
Host SDMA Buffer Boundary in the Block Size register.
The Host Controller generates 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 Host
Controller restarts the SDMA transfer.
When restarting SDMA by the Resume command or by setting
Continue Request in the Block Gap Control register, the Host
Controller shall start at the next contiguous address stored here in
the SDMA System Address register.
ADMA does not use this register.
3403
SPRUH73H – October 2011 – Revised April 2013
Multimedia Card (MMC)
Copyright © 2011–2013, Texas Instruments Incorporated