HD6432646 Hitachi, HD6432646 Datasheet - Page 451

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

12.2
12.2.1
TCNT is an 8-bit readable/writable* up-counter.
When the TME bit is set to 1 in TCSR, TCNT starts counting pulses generated from the internal
clock source selected by bits CKS2 to CKS0 in TCSR. When the count overflows (changes from
H'FF to H'00), an internal reset, a NMI interrupt (only WDT1), or an interval timer interrupt
(WOVI) is generated, depending on the mode selected by the WT/IT bit in TCSR.
TCNT is initialized to H'00 by a reset, in hardware standby mode, or when the TME bit is cleared
to 0. It is not initialized in software standby mode.
Note: * TCNT is write-protected by a password to prevent accidental overwriting. For details see
12.2.2
TCSR0
Note: * Only a 0 may be written to this bit to clear the flag.
TCSR1
Note: * Only a 0 may be written to this bit to clear the flag.
Bit
Initial value :
R/W
Bit
Initial value :
R/W
Bit
Initial value :
R/W
section 12.2.4, Notes on Register Access.
Register Descriptions
Timer Counter (TCNT)
Timer Control/Status Register (TCSR)
:
:
:
:
:
:
R/(W)*
R/(W)*
OVF
OVF
R/W
7
0
7
0
7
0
WT/IT
WT/IT
R/W
R/W
R/W
6
0
6
0
6
0
TME
TME
R/W
R/W
R/W
5
0
5
0
5
0
R/W
PSS
R/W
—
—
4
0
4
1
4
0
RST/NMI
R/W
R/W
—
—
3
0
3
1
3
0
CKS2
CKS2
R/W
R/W
R/W
2
0
2
0
2
0
CKS1
CKS1
R/W
R/W
R/W
1
0
1
0
1
0
CKS0
CKS0
R/W
R/W
R/W
0
0
0
0
0
0
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