UPD17073 NEC, UPD17073 Datasheet - Page 176

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

176
Caution
When executing the HALT instruction that is released when an interrupt request flag (IRQ
for which the corresponding interrupt enable flag (IP
immediately before the HALT instruction.
When the NOP instruction is described immediately before the HALT instruction, time of one
instruction is generated between the IRQ
the case of the CLR1 IRQ
the HALT instruction (Example 1 below). If the NOP instruction is not described immediately
before the HALT instruction, the CRL1 IRQ
instruction, and the HALT mode is not set (Example 2).
Examples 1. To execute HALT instruction correctly
CLR1
NOP
HALT
CLR1
HALT
2. Program that does not set HALT mode
IRQ
1000B
IRQ
1000B
; Sets IRQ
; NOP instruction is described immediately before HALT instruction
; (Clearing IRQ
; HALT instruction is executed correctly (HALT mode is set)
; Sets IRQ
; Clearing IRQ
; (It is reflected on instruction next to HALT instruction)
; HALT instruction is ignored (HALT mode is not set)
instruction, for example, clearing IRQ
is not reflected on HALT instruction
is correctly reflected on HALT instruction)
manipulation instruction and HALT instruction. In
instruction is not correctly reflected on the HALT
) is set, is set, describe a NOP instruction
correctly is reflected upon
PD17072,17073
),