ACE25Q200G Datasheet, PDF (26/46 Pages) ACE Technology Co., LTD. – 2M BIT SPI NOR FLASH Memory Series

ACE25Q200G
2M BIT SPI NOR FLASH Memory Series
Fast Read Quad I/O with “8/16/32/64-Byte Wrap Around”
The Fast Read Quad I/O instruction can also be used to access a specific portion within a page by
issuing a “Set Burst with Wrap” (77h) instruction prior to EBh. The “Set Burst with Wrap” (77h)
instruction can either enable or disable the “Wrap Around” feature for the following EBh instructions.
When “Wrap Around” is enabled, the data being accessed can be limited to either an
8,16,32 or 64-byte section of a 256-byte page. The output data starts at the initial address specified in
the instruction, once it reaches the ending boundary of the 8/16/32/64-byte section, the output will
wrap around to the beginning boundary automatically until /CS is pulled high to
terminate the instruction.
The Burst with Wrap feature allows applications that use cache to quickly fetch a critical address
and then fill the cache afterwards within a fixed length (8/16/32/64-byte) of data without issuing
multiple read instructions.
The “Set Burst with Wrap” instruction allows three “Wrap Bits”, W6-4 to be set. The W4 bit is used to
enable or disable the “Wrap Around” operation while W6-5 are used to specify the length of the wrap
around section within a page.
Similar to a Quad I/O instruction, the Set Burst with Wrap instruction 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. Wrap bit W7 and the lower nibble W3-0 are not used.
Once W6-4 is set by a Set Burst with Wrap instruction, all the following “Fast Read Quad I/O” and
“Word Read Quad I/O” instructions will use the W6-4 setting to access the 8/16/32/64-byte section
within any page. To exit the “Wrap Around” function and return to normal read operation, another Set
Burst with Wrap instruction should be issued to set W4=1. The default value of W4 upon power on is 1.
Table 9
W6
W5
W4 = 0
Wrap Around
Wrap Length
0
0
Yes
8-byte
0
1
Yes
16-byte
1
0
Yes
32-byte
1
1
Yes
64-byte
Figure 16 Set Burst with Wrap Command Sequence
W4 =1 (DEFAULT)
Wrap Around
No
No
No
No
Wrap Length
N/A
N/A
N/A
N/A
Figure 16
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