Renesas H8S/2111B Network Card User Manual


 
Rev. 1.00, 05/04, page 91 of 544
5.8.2 Instructions that Disable Interrupts
The instructions that disable interrupts are LDC, ANDC, ORC, and XORC. After any of these
instructions are executed, all interrupts including NMI are disabled and the next instruction is
always executed. When the I bit or UI bit is set by one of these instructions, the new value
becomes valid two states after execution of the instruction ends.
5.8.3 Interrupts during Execution of EEPMOV Instruction
Interrupt operation differs between the EEPMOV.B instruction and the EEPMOV.W instruction.
With the EEPMOV.B instruction, an interrupt request (including NMI) issued during the transfer
is not accepted until the move is completed.
With the EEPMOV.W instruction, if an interrupt request is issued during the transfer, interrupt
exception handling starts at a break in the transfer cycle. The PC value saved on the stack in this
case is the address of the next instruction. Therefore, if an interrupt is generated during execution
of an EEPMOV.W instruction, the following coding should be used.
L1: EEPMOV.W
MOV.W R4,R4
BNE L1
5.8.4 IRQ Status Register (ISR)
According to the pin status after a reset, IRQnF may be set to 1, so ISR should be read after a reset
to write 0. (n = 7 to 0)