ACE25AB400GFMTH datasheet(13/37 Pages) ACE

13 / 37 page

ACE25AB400G

Serial NOR Flash Memory 4M bits 3.0V Dual I/O Serial Flash Memory with 4KB Uniform Sector

VER 1.1

Dual I/O Fast Read (BBH)

The Dual I/O Fast Read command is similar to the Dual Output Fast Read command but with the

capability to input the 3-byte address (A23-0) and a “Continuous Read Mode” byte 2-bit per clock by SI

and SO, each bit being latched in during the rising edge of SCLK, then the memory contents are shifted

out 2-bit per clock cycle from SI and SO. The command sequence is shown in Figure 11. The first byte

addressed can be at any location. The address is automatically incremented to the next address after

each byte of data is shifted out.

Dual I/O Fast Read with “Continuous Read Mode”

The Dual I/O Fast Read command can further reduce command overhead through setting the

“Continuous Read Mode” bits (M7- 0) after the input 3-byte address (A23-A0). If the “Continuous Read

Mode” bits (M5- 4)=(1, 0), then the next Dual I/O Fast Read command (after CS# is raised and then

lowered) does not require the BBH command code. The command sequence is shown in figure 12. If the

“Continuous Read Mode” bits (M5- 4) do not equal (1, 0), the next command requires the first BBH

command code, thus returning to normal operation. A “Continuous Read Mode” Reset command can be

used to reset (M5- 4) before issuing normal command.

Figure9. Dual I/O Fast Read Sequence Diagram (M5-

4≠(1, 0))

ACE25AB400GFMTH Datasheet(PDF) 13 Page - ACE Technology Co., LTD.