EN25QH256 Datasheet, PDF (37/74 Pages) Eon Silicon Solution Inc. – 256 Megabit Serial Flash Memory with 4Kbyte Uniform Sector

EN25QH256
Read Data Bytes at Higher Speed (FAST_READ) (0Bh)
The device is first selected by driving Chip Select (CS#) Low. The instruction code for the Read Data
Bytes at Higher Speed (FAST_READ) instruction is followed by a 3-byte or 4-byte address (depending
on mode state) and a dummy byte, each bit being latched-in during the rising edge of Serial Clock
(CLK). Then the memory contents, at that address, is shifted out on Serial Data Output (DO), each bit
being shifted out, at a maximum frequency FR, during the falling edge of Serial Clock (CLK).
The instruction sequence is shown in Figure 17. The first byte addressed can be at any location. The
address is automatically incremented to the next higher address after each byte of data is shifted out.
The whole memory can, therefore, be read with a single Read Data Bytes at Higher Speed
(FAST_READ) instruction. When the highest address is reached, the address counter rolls over to
000000h, allowing the read sequence to be continued indefinitely.
The default read mode is 3-byte address, to access higher address (4-byte address) which requires to
enter the 4-byte address read mode. To enter the 4-byte mode, please refer to the enter 4-byte mode
(EN4B) Mode section.
The Read Data Bytes at Higher Speed (FAST_READ) instruction is terminated by driving Chip Select
(CS#) High. Chip Select (CS#) can be driven High at any time during data output. Any Read Data Bytes
at Higher Speed (FAST_READ) instruction, while an Erase, Program or Write cycle is in progress, is
rejected without having any effects on the cycle that is in progress.
The instruction sequence is shown in Figure 17.1 while using the Enable Quad Peripheral Interface
mode (EQPI) (38h) command.
Figure 17. Fast Read Instruction Sequence Diagram
Note: Please note the above address cycles are base on 3-byte address mode, for 4-byte address
mode, the address cycles will be increased.
This Data Sheet may be revised by subsequent versions
37
or modifications due to changes in technical specifications.
©2004 Eon Silicon Solution, Inc.,
Rev. E, Issue Date: 2012/01/30
www.eonssi.com