HD6475328-CP10 Datasheet, PDF (225/459 Pages) Hitachi Semiconductor – original Hitachi CMOS microcomputer unit (MCU)

11.1.3 Input and Output Pins
Table 11-1 lists the input and output pins of the 8-bit timer.
Table 11-1 Input and Output Pins of 8-Bit Timer
Name
Timer output
Timer clock input
Timer reset input
Abbreviation
TMO
TMCI
TMRI
I/O
Output
Input
Input
Function
Output controlled by compare-match
External clock source for the counter
External reset signal for the counter
11.1.4 Register Configuration
Table 11-2 lists the registers of the 8-bit timer.
Table 11-2 8-Bit Timer Registers
Name
Abbreviation R/W
Initial Value Address
Timer control register
TCR
R/W
H'00
H'FFD0
Timer control/status register TCSR
R/(W)* H'10
H'FFD1
Timer constant register A
TCORA
R/W
H'FF
H'FFD2
Timer constant register B
TCORB
R/W
H'FF
H'FFD3
Timer counter
TCNT
R/W
H'00
H'FFD4
* Software can write a “0” to clear bits 7 to 5, but cannot write a “1” in these bits.
11.2 Register Descriptions
11.2.1 Timer Counter (TCNT)—H'FFD4
Bit
7
6
5
4
3
2
1
0
Initial value
Read/Write
0
0
0
0
0
0
0
0
R/W R/W R/W R/W R/W R/W R/W R/W
The timer counter (TCNT) is an 8-bit up-counter that increments on a pulse generated from one of
four clock sources. The clock source is selected by clock select bits 2 to 0 (CKS2 to CKS0) of the
timer control register (TCR). The CPU can always read or write the timer counter.
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