Datasheet
Section 3 Exception Handling 
    Rev. 3.00 Sep. 10, 2007 Page 51 of 528 
   REJ09B0216-0300 
3.2.4  Interrupt Enable Register 2 (IENR2) 
IENR2 enables, timer B1 overflow interrupts. 
Bit Bit Name 
Initial 
Value 
R/W Description 
7, 6   All 0  Reserved 
These bits are always read as 0. 
5  IENTB1  0  R/W  Timer B1 Interrupt Enable 
When this bit is set to 1, timer B1 overflow interrupt 
requests are enabled. 
4 to 0   All 1  Reserved 
These bits are always read as 1. 
When disabling interrupts by clearing bits in an interrupt enable register, or when clearing bits in 
an interrupt flag register, always do so while interrupts are masked (I = 1). If the above clear 
operations are performed while I = 0, and as a result a conflict arises between the clear instruction 
and an interrupt request, exception handling for the interrupt will be executed after the clear 
instruction has been executed. 
3.2.5  Interrupt Flag Register 1 (IRR1) 
IRR1 is a status flag register for direct transition interrupts, RTC interrupts, and IRQ3 to IRQ0 
interrupt requests. 
Bit Bit Name 
Initial 
Value 
R/W Description 
7  IRRDT  0  R/W  Direct Transfer Interrupt Request Flag 
[Setting condition] 
When a direct transfer is made by executing a SLEEP 
instruction while DTON in SYSCR2 is set to 1. 
[Clearing condition] 
When IRRDT is cleared by writing 0 










