HD404669 Series
21
Table 1 Initial Values After MCU Reset
Item
Abbr.
Initial
Value
Contents
Program
counter
(PC)
$0000
Indicates program execution point from start
address of ROM area
Status flag
(ST)
1
Enables conditional branching
Stack pointer
(SP)
$3FF
Stack level 0
Interrupt
flags/mask
Interrupt enable flag
(IE)
0
Inhibits all interrupts
Interrupt request flag
(IF)
0
Indicates there is no interrupt request
Interrupt mask
(IM)
1
Prevents (masks) interrupt requests
I/O
Port data register
(PDR)
All bits 1
Enables output at level 1
Data control register
(DCD0)
0000
Turns output buffer off (to high impedance)
Data control register
(DCD1)
--00
Data control register
(DCD2)
000-
Data control register
(DCR0–DCR4,
DCR6–DCR9)
0000
Data control register
(DCRA)
--00
Port mode register A
(PMRA)
--00
Refer to description of port mode register A
Port mode register B
(PMRB)
0000
Refer to description of R port
Port mode register C
bits 3, 1, 0
(PMRC3,
PMRC1,
PMRC0)
00-
Refer to description of port mode register C
Detection Edge select
registers 1 and 2
(ESR1, 2)
0000
Refer to description of interrupts
Timer/
counters,
serial
interface
Timer mode register A
(TMA)
0000
Refer to description of timer mode register A
section
Timer mode register C1
(TMC1)
0000
Refer to description of timer mode register C1
Timer mode register C2
(TMC2)
-000
Refer to description of timer mode register C2
Timer mode register D1
(TMD1)
0000
Refer to description of timer mode register D1
Timer mode register D2
(TMD2)
0000
Refer to description of timer mode register D2
Serial mode register 1A
(SM1A)
0000
Refer to description of serial mode register
1A
Serial mode register 1B
(SM1B)
--X0
Refer to description of serial mode register
1B
Prescaler S
(PSS)
$000
Refer to description of prescalers
Prescaler W
(PSW)
$00
Refer to description of prescalers
Timer counter A
(TCA)
$00
Refer to description of timer A
Timer counter C
(TCC)
$00
Refer to description of timer C
Timer counter D
(TCD)
$00
Refer to description of timer D