Renesas RL78/F13 User Manual

RL78/F13, F14 CHAPTER 21 INTERRUPT FUNCTIONS
R01UH0368EJ0210 Rev.2.10 1504
Dec 10, 2015
21.3.8 Program status word (PSW)
The program status word is a register used to hold the instruction execution result and the current status for an interrupt
request. The IE flag that sets maskable interrupt enable/disable and the ISP0 and ISP1 flags that control multiple interrupt
servicing are mapped to the PSW.
Besides 8-bit read/write, this register can carry out operations using bit manipulation instructions and dedicated
instructions (EI and DI). When a vectored interrupt request is acknowledged, if the BRK instruction is executed, the contents
of the PSW are automatically saved into a stack and the IE flag is reset to 0. When a maskable interrupt request is
acknowledged, if the value of the bits in the priority specification flag register which correspond to that interrupt is not 00,
the value minus 1 is transferred to the ISP0 and ISP1 flags. The PSW contents are also saved into the stack with the PUSH
PSW instruction. They are restored from the stack with the RETI, RETB, and POP PSW instructions.
Reset signal generation sets PSW to 06H.
Figure 21-10. Configuration of Program Status Word
<7>
IE
<6>
Z
<5>
RBS1
<4>
AC
<3>
RBS0
<2>
ISP1
<1>
ISP0
0
CYPSW
After reset
06H
ISP1
0
0
1
1
Enables interrupt of level 0
(while interrupt of level 1 or 0 is being serviced).
Enables interrupt of level 0 and 1
(while interrupt of level 2 is being serviced).
Enables interrupt of level 0 to 2
(while interrupt of level 3 is being serviced).
Enables all interrupts
(waits for acknowledgment of an interrupt).
IE
0
1
Disabled
Enabled
Priority of interrupt currently being serviced
Interrupt request acknowledgment enable/disable
Used when normal instruction is executed
ISP0
0
1
0
1

Renesas RL78/F13 Specifications

General

Brand	Renesas
Model	RL78/F13
Category	Computer Hardware
Language	English