mx25l3237d Macronix International Co., mx25l3237d Datasheet - Page 19

• Manufacturer Part Number: mx25l3237d
• Description: Serial Flash Memory
• Manufacturer: Macronix International Co.

P/N: PM1393
Hardware Protected Mode (HPM):
-
Note:
To exit the hardware protected mode requires WP#/SIO2 driving high once the hardware protected mode is entered. If the
WP#/SIO2 pin is permanently connected to high, the hardware protected mode can never be entered; only can use software
protected mode via BP3, BP2, BP1, BP0.
If the system goes into four I/O read mode, the feature of HPM will be disabled.
(6) Read Data Bytes (READ)
The read instruction is for reading data out. The address is latched on rising edge of SCLK, and data shifts out on the falling
edge of SCLK at a maximum frequency fR. The first address byte can be at any location. The address is automatically
increased to the next higher address after each byte data is shifted out, so the whole memory can be read out at a single
READ instruction. The address counter rolls over to 0 when the highest address has been reached.
The sequence of issuing READ instruction is: CS# goes low-> sending READ instruction code-> 3-byte address on SI
-> data out on SO-> to end READ operation can use CS# to high at any time during data out. (see Figure 14)
(7) Read Data Bytes at Higher Speed (FAST_READ)
The FAST_READ instruction is for quickly reading data out. The address is latched on rising edge of SCLK, and data of
each bit shifts out on the falling edge of SCLK at a maximum frequency fC. The first address byte can be at any location.
The address is automatically increased to the next higher address after each byte data is shifted out, so the whole memory
can be read out at a single FAST_READ instruction. The address counter rolls over to 0 when the highest address has
been reached.
The sequence of issuing FAST_READ instruction is: CS# goes low-> sending FAST_READ instruction code-> 3-byte
address on SI-> 1-dummy byte (default) address on SI->data out on SO-> to end FAST_READ operation can use CS#
to high at any time during data out. (see Figure 15)
While Program/Erase/Write Status Register cycle is in progress, FAST_READ instruction is rejected without any impact
on the Program/Erase/Write Status Register current cycle.
(8) 2 x I/O Read Mode (2READ)
The 2READ instruction enable double throughput of Serial Flash in read mode. The address is latched on rising edge of
SCLK, and data of every two bits(interleave on 2 I/O pins) shift out on the falling edge of SCLK at a maximum frequency
fT. The first address byte can be at any location. The address is automatically increased to the next higher address after
each byte data is shifted out, so the whole memory can be read out at a single 2READ instruction. The address counter
rolls over to 0 when the highest address has been reached. Once writing 2READ instruction, the following address/dummy/
data out will perform as 2-bit instead of previous 1-bit.
The sequence of issuing 2READ instruction is: CS# goes low
on SIO1 & SIO0
can use CS# to high at any time during data out (see Figure 16 for 2 x I/O Read Mode Timing Waveform).
While Program/Erase/Write Status Register cycle is in progress, 2READ instruction is rejected without any impact on the
Program/Erase/Write Status Register current cycle.
When SRWD bit=1, and then WP#/SIO2 is low (or WP#/SIO2 is low before SRWD bit=1), it enters the hardware
protected mode (HPM). The data of the protected area is protected by software protected mode by BP3, BP2, BP1,
BP0 and hardware protected mode by the WP#/SIO2 to against data modification.
4-bit dummy cycle on SIO1 & SIO0
data out interleave on SIO1 & SIO0
19
sending 2READ instruction
MX25L3237D
24-bit address interleave
to end 2READ operation
REV. 0.02, JUN. 13, 2008