EM6605 EM Microelectronic, EM6605 Datasheet - Page 13

• Manufacturer Part Number: EM6605
• Description: 4 bit Microcontroller
• Manufacturer: EM Microelectronic

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.
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.
6.6. PortC registers
Table 18.PortC input/output register - PortC
Table 19.PortC Interrupt request register - IRQpC
Table 20.PortC interrupt mask register - MportC
Bit
3
2
1
0
Bit
3
2
1
0
Bit
3
2
1
0
Name
PC3
PC2
PC1
PC0
Name
IRQpc3
IRQpc2
IRQpc1
IRQpc0
Name
MPC3
MPC2
MPC1
MPC0
Reset
-
-
-
-
Reset
0
0
0
0
Reset
0
0
0
0
R/W
R/W
R /W
R/W
R /W
R/W
R
R
R
R
R/W
R/W
R/W
R/W
R/W
Table 17.Ports A&C Interrupt Request
IRQPA
0
0
1
1
0
1
1
PC3 I/O data
PC2 I/O data
PC1 I/O data
PC0 I/O data
input PC3 interrupt request flag
input PC2 interrupt request flag
input PC1 interrupt request flag
input PC0 interrupt request flag
interrupt mask for input PC3
interrupt mask for input PC2
interrupt mask for input PC1
interrupt mask for input PC0
Description
Description
Description
IRQPC
0
1
0
1
1
0
1
© EM Microelectonic-Marin SA, 02/99, Rev. B/243
PA&C
X
0
0
0
1
1
1
No
Yes
Yes
Yes
No
No
Yes
EM6605
Request to CPU
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