Epson S1C63666, Техническое руководство

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S1C63666 TECHNICAL MANUAL
EPSON
37
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Input Ports)
4.5 Input Ports (K00–K03 and K10–K13)
4.5.1 Configuration of input ports
The S1C63666 has eight bits of general-purpose input ports (K00–K03, K10–K13). Each input port termi-
nal provides an internal pull-down resistor that can be enabled by mask option.
Figure 4.5.1.1 shows the configuration of input port.
Kxx
Mask option
Address
V
DD
Interrupt
request
Data bus
V
SS
Fig. 4.5.1.1 Configuration of input port
Selection of "With pull-down resistor" with the mask option suits input from the push switch, key matrix,
and so forth. When "Gate direct" is selected, the port can be used for slide switch input and interfacing
with other LSIs.
The K00 and K01 input ports can also be used as the Run/Stop and Lap direct inputs for the stopwatch
timer, and the K13 port can also be used as the event counter input for the programmable timer.
4.5.2 Interrupt function
All eight bits of the input ports (K00–K03, K10–K13) provide the interrupt function. The conditions for
issuing an interrupt can be set by the software. Further, whether to mask the interrupt function can be
selected by the software.
Figure 4.5.2.1 shows the configuration of K00–K03 (K10–K13) interrupt circuit.
Input comparison
register (KCP00, 10)
K00, 10
Interrupt
request
Interrupt selection
register (SIK00, 10)
Address
Address
Address
Address
Interrupt factor
flag (IK0, 1)
K01, 11
K02, 12
K03, 13
Interrupt mask
register (EIK0, 1)
Address
Data bus
Fig. 4.5.2.1 Input interrupt circuit configuration