HB28E016/D032/D064/B128MM2
48
Command Response Timings
All timing diagrams use the following schematics and abbreviations:
S: Start bit (= 0)
T: Transmitter bit (Host = 1, Card = 0)
P: One-cycle pull-up (= 1)
E: End bit (= 1)
Z: high impedance state (-> = 1)
D: Data bits
*: repeater
CRC: Cyclic redundancy check bits (7 bits for command or response, 16 bits for block data)
The difference between the P-bit and Z-bit is that a P-bit is actively driven to HIGH by the card
respectively host output driver, while the Z-bit is driven to (respectively kept) HIGH by the pull-up
resistors R
CMD
respectively R
DAT
. Actively driven P-bits are less sensitive to noise superposition. For the
timing of these Hitachi MultiMediaCards, the following values are defined:
Timing Values
Value [clock cycles]
Symbol
Min
Max
Description
N
CR
2
64
Number of cycles between command and
response
N
ID
5
5
Number of cycles between card identification
or card operation conditions command and the
corresponding response
N
AC
2*
1
TAAC + NSAC*
2
Number of cycles between a command and
the start of a related data block
N
RC
8
—
Number of cycles between the last response
and a new command
N
CC
8
—
Number of cycles between two commands, if
no response will be sent after the first
command (e.g. broadcast)
N
WR
2
—
Number of cycles between a write command
and the start of a related data block
N
ST
2
2
Number of cycles between stop command and
valid read / write data end
Notes: 1. Refer to Chapter “Electrical Characteristics” for more details about the access time.
2. Refer to Chapter “Time-out Condition”.