User Manual

Secure Digital (SD) Bus Protocol Description
4-6 TriFlash with SD Interface Product Manual (Preliminary), Rev. 1.2 © 2002/2003 SANDISK CORPORATION
Power on
Card is busy or
host omitted
voltage range
Idle State
(idle)
ACMD41
Ready State
(ready)
CMD2
Identification
State (ident)
CMD3
Stand-by-State
(stby)
CMD0
From all states except (ina)
Inactive State
(ina)
CMD15
Cards with non-compatible
voltage range
Card-identification mode
Data-transfer mode
From all states in
data-transfer mode
No Response
(Non valid command)
Must be a
MultiMediaCard
CMD3
SPI Operation
Mode
Card responds
with new RCA
Start MultiMediaCard
initialization process
starting at CMD1
CMD0
CS Asserted "0"
Figure 4-7. SD Bus State Diagram (Card Identification Mode)
4.3.1. Reset
GO_IDLE_STATE (CMD0) is the software reset command and sets each TriFlash to Idle State regardless of the
current device state. TriFlash devices in Inactive State are not affected by this command.
After power-on by the host, all TriFlash devices are in Idle State, including the devices that were in Inactive State.
Note that at least 74 clock cycles are required prior to starting bus communication.
After power-on or CMD0, all TriFlash devices’ CMD lines are in input mode, waiting for the start bit of the next
command. The devices are initialized with a default relative card address (RCA=0x0000) and with a default driver
stage register setting (lowest speed, highest driving current capability).