HD404654 Datasheet, PDF (15/109 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

HD404654 Series
Table 1 Initial Values After MCU Reset
Item
Program counter
Status flag
Stack pointer
Interrupt
flags/mask
I/O
Timer/counters,
serial interface
Abbr.
(PC)
Interrupt enable flag
(ST)
(SP)
(IE)
Initial Value Contents
$0000
Indicates program execution point
from start address of ROM area
1
Enables conditional branching
$3FF
Stack level 0
0
Inhibits all interrupts
Interrupt request flag
Interrupt mask
Port data register
Data control register
Port mode register A
(IF)
0
(IM)
1
(PDR) All bits 1
(DCD0– All bits 0
DCD2)
(DCR0– All bits 0
DCR4)
(PMRA) - - 00
Port mode register B (PMRB) - - - 0
Port mode register C
bits 3, 1, 0
(PMRC3, 000 -
PMRC1,
PMRC0)
Detection edge select (ESR2) 00 - -
register 2
Timer mode register A (TMA) - 000
Timer mode register
C1
Timer mode register
C2
Timer mode register
D1
Timer mode register
D2
Serial mode register
1A
Serial mode register
1B
Prescaler S
Timer counter A
(TMC1) 0000
(TMC2) - 000
(TMD1) 0000
(TMD2) 0000
(SM1A) 0000
(SM1B) - - X0
(PSS)
(TCA)
$000
$00
Indicates there is no interrupt request
Prevents (masks) interrupt requests
Enables output at level 1
Turns output buffer off (to high
impedance)
Refer to description of port mode
register A
Refer to description of port mode
register B
Refer to description of port mode
register C
Disables edge detection
Refer to description of timer mode
register A
Refer to description of timer mode
register C1
Refer to description of timer mode
register C2
Refer to description of timer mode
register D1
Refer to description of timer mode
register D2
Refer to description of serial mode
register 1A
Refer to description of serial mode
register 1B
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