mx25l12855e Macronix International Co., mx25l12855e Datasheet - Page 30

• Manufacturer Part Number: mx25l12855e
• Description: Secured Serial Flash
• Manufacturer: Macronix International Co.

MX25L12855E
(28) GPIO Expander
GPIO expander is used for microcontrollers to expand the general purpose I/O pin with 7 extra General Purpose In-
put/Outputs. The outputs provided can be used for controlling simple on-off of system components.
(28-1) GPIO Function Enable (GPIOEN)
The GPIOEN instruction is for enabling the function of GPIO mode. For all of GPIO commands like GPIORW, GPI-
ORST, and GPIODIS, they should be issued after GPIOEN is set. GPIO is not allowed in parallel mode and POR
read, but it is allowed in the other modes even in Deep Power down (DPW). If GPIO is active in DPW mode, the I
SB2
may increase more than 40uA (see Table 9).
The sequence of issuing GPIOEN instruction is: CS# goes low -> GPIOEN instruction code is sent -> CS# goes
high.
The CS# must go high exactly at the byte boundary; otherwise, the instruction will be rejected and not executed.
(28-2) GPIO Function Disable (GPIODIS)
The GPIODIS instruction is for disabling the function of GPIO mode. Moreover, the GPIO function is also disabled
after POR, and all of the GPIO registers will be reset if GPIO function is disabled. GPIOEN should be issued before
the setting of GPIODIS instruction to make sure the GPIO function is enabled, or the GPIODIS instruction will not be
executed. After GPIODIS is issued, other GPIO command will not be executed until GPIOEN is set again.
The sequence of issuing GPIODIS instruction is: CS# goes low -> GPIODIS instruction code is sent -> CS# goes
high.
The CS# must go high exactly at the byte boundary; otherwise, the instruction will be rejected and not executed.
(28-3) GPIO Register Read/Write (GPIORW)
The GPIORW instruction is for changing the GPIO registers. Read and Write operation can be judged by bit7 of ad-
dress byte. Read operation will be executed when bit7 = 1 and write operation will be executed when bit7 = 0. The
read/write operation is described in Table 10. GPIOEN should be issued before the setting of GPIORW instruction to
make sure the GPIO function is enabled, or the GPIORW instruction will not be executed.
The sequence of issuing GPIORW instruction is: CS# goes low -> GPIORW instruction code is sent -> issue R/W#
bit (Write as 0; Read as 1) and address bit (A6~A0) ->SI/SO 8 bit data in/out cycle -> CS# goes high.
The GPIO read/write waveform is shown as Figure 40 and Figure 41.
The CS# must go high exactly at the byte boundary; otherwise, the instruction will be rejected and not executed.
(28-4) GPIO Register Reset (GPIORST)
The GPIORST instruction is for resetting all the GPIO registers. The GPIO registers will be reset to 0 (default value)
if GPIORST or POR is issued. GPIOEN should be issued before the setting of GPIORST instruction to make sure
P/N: PM1466
REV. 0.05, MAR. 05, 2009
30