Rev. 1.0
115
Si4010-C2
In assembly:
orl P0, #00001110B ; Turn GPIO[3:1] as inputs
anl P0CON, #NOT 00001110B
anl PORT_CTRL, #NOT(M_PORT_MATRIX OR M_PORT_ROFF)
orl PORT_CTRL, #M_PORT_MATRIX ; Set Matrix mode and keep resistors
orl PORT_CTRL, #M_PORT_STROBE ; Strobe new Matrix/Roff modes to GPIO
anl PORT_CTRL, #NOT(M_PORT_STROBE)
30.5. Special GPIO Modes Control
Some of the GPIO serves multiple purposes. Special configuration registers PORT_CTRL and PORT_SET
are used to configure GPIO for other purpose then regular GPIO. Some GPIO can server multiple special
purposes.
Table 30.4 shows all the functionality the GPIO can assume along with control signals and priority of the
functionality. The lower the priority number, the higher the functional priority. For example, if the functional-
ity with priority 1 is programmed, then controls selecting functionality of priority 2 and above will be ignored
no matter what the control settings are.