Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
130
5.7.2 Extension Register Commands
5.7.2.1 Extension Register Read Command (Single Block)
Figure 5-4 shows definition of Read Extension Register Single Block Command (CMD48). Bus timing of
this command is equivalent to a single block read command (CMD17). The response type is R1. Data
block length is fixed to 512-byte length.
Figure 5-4 : Read Extension Register Single Block Command (CMD48)
Fields in the argument of CMD48:
MIO: Selection of Memory Space or I/O Space (0: Memory Space, 1: I/O Space)
There are two independent spaces; Memory Extension Register Space and I/O Extension
Register Space. Which space accessed is selected by this bit. I/O Extension Register Space is
equivalent to CMD52/53 SDIO space. (Refer to Part E1 SDIO Specification and Part E7 iSDIO
Specification.)
FNO: Function Number
Unique Function Number is assigned to each function. FNO helps host to distinguish functions
and enables card to check sequence of commands. Up to 15 functions may be assigned for
memory and up to 7 functions may be assigned for I/O.
ADDR: Address of Extension Register Space
Lower 9-bit is used as offset address in a page and upper 8-bit is used as page number. Up to
256 pages is addressable.
LEN: Effective Length of a Page
On accessing Data Port, card ignores this field but host shall set this field to 000h. If access is
not to Data Port, this field is used to set effective data length (byte unit) in a page.
Figure 5-5 shows read timing of Extension Register. The register area for read is specified by ADDR
and LEN and shall be in a page boundary. The register data is set from the top of 512-byte data block
and the rest is filled with dummy data. If data length is specified over a page boundary (512 bytes),
surplus data in next page is not read and not set in the data block. The maximum data access time from
Length
Length (9
-bit for Register Access)
000h: 1byte
001h: 2 bytes
002h: 3 bytes
............
1FFh: 512 bytes
Memory or I/O
0b: Memory Extension
1b: I/O Extension
16-
08
38-
35
xxxx
FNO
34
33-
17
17-bit
ADDR
0
rsv
xxxxxxxxx
LEN
0
07
-01
3945
-
4046
47
x
MIO
1xxxxxxx
11000010
E
CRC7INDEX
TS
16
-08
38
-35
xxxx
FNO
34
33
-17
17-bit
ADDR
0
rsv
xxxxxxxxx
LEN
007
-
0139
45-
40
4647
x
MIO
1
xxxxxxx11000010
E
CRC7
INDEXT
S
Address (17-
bit)
There are two independent spaces; Memory Space (MIO=0)
and I/O Space (MIO=1) up to 128KB for each function.
Function No.
Memory Space (MIO=0 4-bit Bit38-
35)
0000b: Function 0
0001b: Function 1
..............
1111b: Function 15
I/O Space (MIO=1 3-bit Bit38-36, Bit35=0)
000b: Function 0
001b: Function 1
..............
111b: Function 7