HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 122

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

5.5.2 Instructions that Inhibit Interrupts
The LDC, ANDC, ORC, and XORC instructions inhibit interrupts. When an interrupt occurs,
after determining the interrupt priority, the interrupt controller requests a CPU interrupt. If the
CPU is currently executing one of these interrupt-inhibiting instructions, however, when the
instruction is completed the CPU always continues by executing the next instruction.
5.5.3 Interrupts during EEPMOV Instruction Execution
The EEPMOV.B and EEPMOV.W instructions differ in their reaction to interrupt requests.
When the EEPMOV.B instruction is executing a transfer, no interrupts are accepted until the
transfer is completed, not even NMI.
When the EEPMOV.W instruction is executing a transfer, interrupt requests other than NMI are
not accepted until the transfer is completed. If NMI is requested, NMI exception handling starts at
a transfer cycle boundary. The PC value saved on the stack is the address of the next instruction.
Programs should be coded as follows to allow for NMI interrupts during EEPMOV.W execution:
5.5.4 Notes on External Interrupts during Use
If the IRQnF flag is at IRQnF = 1, after reading the IRQnF flag if the IRQnF flag writes 0 clear
status is reached. However, there are times when clear status occurs in error and interrupt
processing is not executed when the IRQnF flag is at 0 although IRQnF = 1 was not attained. This
occurs in when the following conditions are fulfilled.
•
1.
2.
3.
•
1.
L1: EEPMOV.W
Setting conditions
When using multiple external interrupts (IRQa, IRQb)
IRQaF flag clears because 0 is written, and IRQbF flag clears by the hardware.
IRQaF flag clears and bit operation command is being used for the IRQ status resistor (ISR)
or the ISR is being read in bytes; IRQaF flag's bits clear and other bit values read in bits are
written in bytes.
Occurrence conditions
When IRQaF = 1, for the IRQaF flag to clear, ISR resistor read is executed. Thereafter
interrupt processing is carried out and IRQbF flag clears.
MOV.W R4,R4
BNE
L1
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