upd17240 Renesas Electronics Corporation., upd17240 Datasheet - Page 62

• Manufacturer Part Number: upd17240
• Description: 4-bit Single-chip Microcontrollers For Small General-purpose Infrared Remote Control Transmitters
• Manufacturer: Renesas Electronics Corporation.

8.
8.1
address, which is called a vector address. A vector address is assigned to each interrupt source, as shown in Table
8-1.
starting from the one with the highest priority.
an interrupt is acknowledged is that the interrupt is enabled by the EI instruction. While the DI instruction is executed,
or while an interrupt is acknowledged, the interrupt is disabled.
executed before the RETI instruction. Acknowledging the interrupt is enabled by the EI instruction after the instruction
next to the EI instruction has been executed. Therefore, no interrupt can be acknowledged between the EI and RETI
instructions.
62
µ PD17246 is provided with three interrupt sources.
When an interrupt has been acknowledged, the program execution automatically branches to a predetermined
Remark 0001H is normal address
When more than one interrupt request is issued at the same time, the interrupts are acknowledged in sequence,
Whether an interrupt is enabled or disabled is specified by the EI or DI instruction. The basic condition under which
To enable acknowledgement of an interrupt after the interrupt has been processed, the EI instruction must be
Caution In interrupt processing, only the BCD, CMP, CY, Z, IXE flags are automatically saved to the stack
INTERRUPT FUNCTIONS
Interrupt Sources
Priority
by the hardware, to a maximum of three levels. Also, within the interrupt processing contents,
when peripheral hardware (timer, A/D converter, etc. ) is accessed, the DBF and WR contents
are not saved by the hardware. Accordingly, it is recommended that at the beginning of interrupt
processing, DBF and WR be saved by software to RAM, and immediately before finishing
interrupt processing, the saved contents be returned to their original location.
1
2
3
8-bit timer
INT pin rising and falling edges
Basic interval timer
µ PD17240, 17241, 17242, 17243, 17244, 17245, 17246
Interrupt Source
Table 8-1. Vector Address
Data Sheet U15002EJ1V1DS
External
Internal
Internal
Ext/Int
Vector Address
0004H
0003H
0002H