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TriFlash Interface Description

3-7

Logic working level

Supply voltage

Supply ramp up time

Bus master sup ply voltage

ACMD

max

Valid voltage range

for commands

CMD0, 15, 55 and

ACMD41.

Valid voltage

range for all

other com-

mands and

memory access.

Power up time

Initialization delay:

The maximum of

CMD2

1 msec, 74 clock cycles

and supply ramp up time.

Initialization sequence

ACMD

min

time

Time out value for initialization process = 100 msec.

Optional repetitions of ACMD41

until no cards are responding

with busy bit set.

Figure 3-5. Power-up Diagram

After power up the TriFlash enters the idle state. During this state the TriFlash ignores all bus transactions until

ACMD41 is received (ACMD command type shall always precede with CMD55).

ACMD41 is a special synchronization command used to negotiate the operation voltage range and to poll the

devices until they are out of their power-up sequence. Besides the operation voltage profile of the devices, the

response to ACMD41 contains a busy flag, indicating that the device is still working on its power-up procedure and

is not ready for identification. This bit informs the host that the device is not ready. The host has to wait (and

continue to poll the devices, each one on his turn) until this bit is cleared. The maximum period of power up

procedure of single device shall not exceed 1 second.

Getting individual devices, as well as the whole TriFlash system, out of idle state is up to the responsibility of the

bus master. Since the power up time and the supply ramp up time depend on application parameters such as the

maximum number of TriFlash devices, the bus length and the power supply unit, the host must ensure that the

power is built up to the operating level (the same level which will be specified in ACMD41) before ACMD41 is

transmitted.

After power up, the host starts the clock and sends the initialising sequence on the CMD line. This sequence is a

contiguous stream of logical ‘1’s. The sequence length is the maximum of 1msec, 74 clocks or the supply-ramp-up-

time. The additional 10 clocks (over the 64 clocks after what the device should be ready for communication) are

provided to eliminate power-up synchronization problems.

Every bus master shall have the capability to implement ACMD41 and CMD1. CMD1 will be used to ask the

TriFlash to send their Operation Conditions. In any case the ACMD41 or the CMD1 shall be send separately to each

device accessing it through its own CMD line.