455A Datasheet, PDF (32/148 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

455A Group
High-speed on-chip oscillator
XIN
Ceramic resonance
XN
Quartz-crystal
oscillation
Low-speed on-chip oscillator
MR1, MR0
00
01
10
11
Division circuit
Divided by 8
Divided by 4
Divided by 2
MR3, MR2
11
10
01
00
System clock (STCK)
Internal clock
generating circuit
(divided by 3)
Instruction clock
(INSTCK)
PA0
Prescaler (8)
ORCLK
(TABPS)
Reload register RPS (8)
(TPSAB)
(TPSAB)
(TPSAB)
Register B Register A
(TABPS)
D5/INT
I13
I10
C/CNTR
W13
T1UDF
PWMOUT
ORCLK
T3UDF
W40
0
W11, W10
00
01
10
11
W12
1
PWMOUT
I12
One-sided edge
I11
0
detection circuit
0
I10
Both edges
SQ
1
1
detection circuit
1
R
0
Timer 1 (8)
T1F
(TAB1)
Reload register R1 (8)
(T1AB) (TR1AB) (T1AB)
(T1AB)
Register B Register A
(TAB1)
Timer 1
interrupt
Timer 1 underflow signal
(T1UDF)
Port C output
W11 W10
D
QR T
W12
T1UDF
W41
Register B Register A
(T2HAB)
Reload register R2H (8)
W20
XIN
0
ORCLK 1/2
1
Timer 2 (8)
Reload control circuit
“H” interval
expansion
W21
(TAB2)
(T2R2L)
Reload register R2L (8)
(T2AB) _(T2AB) (T2AB)
(TAB2)
Register B Register A
W22
1
0
Q T PWMOD
R
W23
T2F
Timer 2
interrupt
Data is set automatically from each reload register
when timer underflows (auto-reload function).
Fig 33. Timers structure (1)
Rev.1.01 Feb 15, 2008 Page 32 of 146
REJ03B0224-0101