EM6603
6.5 PortC
This port can be configured as either input or output (not bitwise selectable). When in input mode it implements
the identical interrupt functions as PortA. The PortC register is used to read data when input mode and to write
data when in output mode. Input mode is set by writing 0 to the I/O control bit CIOPC in register CPIOB and the
input becomes high impedance. On each terminal Pull-Up/Down resistor can be selected by metal option which
are active only when selected as input.
The output mode is selected by writing 1 to CIOPC bit, and the terminal follows the bits in the PortC register.
When PortC is used as an input, interrupt functions as described for PortA can be enabled. Input to the interrupt
logic can be direct or via a debounced input. With the debPCN bit at 0 in the Option register all the PortC inputs
are debounced and with the debPCN bit at 1 none of the PortC inputs are debounced. MPortC is the interrupt
mask register for this port and IRQpC is the portC interrupt request register. See also section 9.
By writing the PA&C bit in the CPIOB data register it is
possible to combine PortA and PortC interrupt
requests (logic AND) as shown in Table 16.
Table 16.Ports A&C Interrupt Request
IRQPA IRQPC PA&C Request to CPU
0
0
1
1
0
1
1
0
1
0
1
1
0
1
X
0
0
0
1
1
1
No
Yes
Yes
Yes
No
At initial reset, the CPIOC control register is set to 0,
and the port is in input mode. The MPortC register is
also set to 0, therefore disabling interrupts.
No
Yes
6.6 PortC registers
Table 17.PortC input/output register - PortC
Bit
Name
PC3
PC2
PC1
PC0
Reset
R/W
R/W
R /W
R/W
R /W
Description
PC3 I/O data
PC2 I/O data
PC1 I/O data
PC0 I/O data
3
-
-
-
-
2
1
0
Table 18.PortC Interrupt request register - IRQpC
Bit
Name
Reset
R/W
Description
3
IRQpc3
IRQpc2
IRQpc1
IRQpc0
0
0
0
0
R
input PC3 interrupt request flag
input PC2 interrupt request flag
input PC1 interrupt request flag
input PC0 interrupt request flag
2
R
1
0
R
R
Table 19.PortC interrupt mask register - MportC
Bit
Name
MPC3
MPC2
MPC1
MPC0
Reset
R/W
R/W
R/W
R/W
R/W
Description
3
0
0
0
0
interrupt mask for input PC3
interrupt mask for input PC2
interrupt mask for input PC1
interrupt mask for input PC0
2
1
0
03/02 REV. G/439
12
www.emmicroelectronic.com
Copyright 2002, EM Microelectronic-Marin SA
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
