Table of Contents
Advertisement
CHAPTER 18 DTP/EXTERNAL INTERRUPT CIRCUIT
●
Switching between the external interrupt function and the DTP function
Switching between the external interrupt function and the DTP function is accomplished by the ISE bit of
the corresponding interrupt control register (ICR). If the ISE bit is "1", the extended intelligent I/O service
2
(EI
OS) is enabled and the circuit executes its DTP function. If it is "0", EI
executes the its external interrupt function.
Note:
If multiple interrupt requests are assigned to a single ICR register, the interrupt level (IL2 to IL0) is
common to all of the interrupt requests. As a rule, when one interrupt request uses EI
interrupt requests cannot use it.
■ Operation of the DTP/external Interrupt Circuit
Table 18.5-1 shows the control bits and interrupt causes of the DTP/external interrupt circuit.
Table 18.5-1 Control Bit and Interrupt Cause of the DTP/external Interrupt Circuit
Interrupt request flag bit
Interrupt request enable bit
Interrupt cause
When DTP/external input requests are set, the resource will generate an interrupt request signal to the
interrupt controller whenever an interrupt cause indicated in the request level setting register (ELVR) is
received at the corresponding pin. If the ISE bit is "0", the interrupt processing microprogram is executed.
If it is "1", the extended intelligent I/O service handling (DTP handling) microprogram is executed.
526
DTP/external interrupt circuit
EIRR: ER7 to ER0
ENIR: EN7 to EN0
Input of an effective edge or level to pin INT7 to INT0
2
OS is disabled and the circuit
2
OS, the other
Advertisement
Table of Contents
