T25S16AFEPR datasheet(53/74 Pages) HMSEMI

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raised and then lowered) does not require the E3h instruction code, as shown in Figure 7.24. This reduces the

instruction sequence by eight clocks and allows the Read address to be immediately entered after CS# is

asserted low. If the “Continuous Read Mode” bits M5-4 do not equal to (1,0), the next instruction (after CS# is

raised and then lowered) requires the first byte instruction code, thus returning to normal operation. It is

recommended to input FFh on IO0 for the next instruction (8 clocks), to ensure M4= 1 and return the device to

normal operation.

Figure 7.23 Octal Word Read Quad I/O Instruction(Initial command or previous M5-4 ≠10)

Figure 7.24 Octal Word Read Quad I/O Instruction(Initial command or previous M5-4 =10)

7.3.9 Set Burst with Wrap (77h)

The Set Burst with Wrap (77h) command is used in conjunction with “Fast Read Quad I/O” commands to

access a fixed length and alignment of 8/16/32/64-bytes of data. Certain applications can benefit from this

feature and improve the overall system code execution performance. This command loads the W4,W5,W6

bits. Similar to a Quad I/O command, the Set Burst with Wrap command is initiated by driving the CS# pin low

and then shifting the instruction code “77h” followed by 24-dummy bits and 8 “Wrap Bits”, W7-0. The

command sequence is shown in Figure 7.25, Set Burst with Wrap Command Sequence. Wrap bit W7 and the

lower nibble W3-0 are not used.

W6, W5

W4=0

W4=1(DEFAULT)

Wrap Around

Wrap Length

Wrap Around

Wrap Length

0,0

Yes

8-byte

N/A

0,1

Yes

16-byte

N/A

1,0

Yes

32-byte

N/A

1,1

Yes

64-byte

N/A

Once W6-4 is set by a Set Burst with Wrap command, all the following “Fast Read Quad I/O” commands

will use the W6-4 setting to access the 8/16/32/64-byte section of data. Note, Status Register-2 QE bit

(SR2[1]) must be set to 1 in order to use the Fast Read Quad I/O and Set Burst with Wrap commands. To exit

the “Wrap Around” function and return to normal read operation, another Set Burst with Wrap command

should be issued to set W4 = 1. The default value of W4 upon power on is 1.

In QPI mode, the “Burst Read with Wrap (0Ch)” instruction should be used to perform the Read operation

HM25Q128A

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