IS25LD256C
DEVICE OPERATION (CONTINUED)
READ COMMAND (READ DATA) OPERATION
The Read Data (READ) instruction is used to read
memory data of a IS25LD256C under normal mode
running up to 33 MHz.
The READ instruction code is transmitted via the Sl
line, followed by three address bytes (A23 - A0) of the
first memory location to be read. A total of 24 address
bits are shifted in, but only AMS (most significant
address) - A0 are decoded. The remaining bits (A23 –
AMS) are ignored. The first byte addressed can be at
any memory location. Upon completion, any data on
the Sl will be ignored. Refer to Table 12 for the related
Address Key.
The first byte data (D7 - D0) addressed is then shifted
out on the SO line, MSb first. A single byte of data, or
up to the whole memory array, can be read out in one
READ instruction. The address is automatically
incremented after each byte of data is shifted out. The
read operation can be terminated at any time by driving
CE# high (VIH) after the data comes out. When the
highest address of the devices is reached, the address
counter will roll over to the 000000h address, allowing
the entire memory to be read in one continuous READ
instruction.
Table 12. Address Key
Address
AN (AMS – A0)
Don't Care Bits
IS25LD256C
A14 - A0
A23 – A15
Figure 12. Read Data Sequence
SIO
Integrated Silicon Solution, Inc.- www.issi.com
17
Rev. A
09/11/2012