LPC47M192-NW Standard Microsystems (SMSC), LPC47M192-NW Datasheet - Page 116

• Manufacturer Part Number: LPC47M192-NW
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LPC47M192-NW

• Lead Free Status / RoHS Status: Compliant

7.12.4 GPIO OPERATION
The operation of the GPIO ports is illustrated in FIGURE 7.
Note:
When the following functions are selected, the associated GPIO pins have bi-directional functionality:
P12, P16, P17 and game port x-axis and y-axis inputs (J1X, J1Y, J2X, J2Y).
When a GPIO port is programmed as an input, reading it through the GPIO data register latches either the inverted or
non-inverted logic value present at the GPIO pin. Writing to a GPIO port that is programmed as an input has no
effect (Table 55)
When a GPIO port is programmed as an output, the logic value or the inverted logic value that has been written into
the GPIO data register is output to the GPIO pin. Reading from a GPIO port that is programmed as an output returns
the last value written to the data register (Table 55). When the GPIO is programmed as an output, the pin is
excluded from the PME and SMI logic.
The LPC47M192 provides 31 GPIOs that can directly generate a PME. See the table in the next section. The
polarity bit in the GPIO control registers select the edge on these GPIO pins that will set the associated status bit in
the PME_STS 2 register. The default is the low-to-high edge. If the corresponding enable bit in the PME_EN 2
register and the PME_EN bit in the PME_EN register is set, a PME will be generated. These registers are located in
the PME_BLK of runtime registers which are located at the address contained in the configuration registers 0x60 and
SMSC DS – LPC47M192
GPx_nIOW
HOST OPERATION
GPx_nIOR
FIGURE 7 is for illustration purposes only and is not intended to suggest specific implementation details.
WRITE
READ
SD-bit
Data Register
Transparent
D-TYPE
D
Q
Bit-n
GPIO
LATCHED VALUE OF GPIO PIN
NO EFFECT
Q
D
FIGURE 7 - GPIO FUNCTION ILLUSTRATION
GPIO INPUT PORT
Table 55 – GPIO Read/Write Behavior
0
1
DATASHEET
Page 116
GPIO
Configuration
Register bit-1
(Polarity)
LAST WRITE TO GPIO DATA REGISTER
BIT PLACED IN GPIO DATA REGISTER
GPIO OUTPUT PORT
GPIO
Configuration
Register bit-0
(Input/Output)
GPIO
PIN
Rev. 03/30/05