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(1) 8-bit compare registers (CR10, CR20)
These are 8-bit registers that compare the value set to CR10 with the 8-bit timer register 1 (TM1) count value,
and the value set to CR20 with the 8-bit timer register 2 (TM2) count value, and, if they match, generate an interrupt
request (INTTM1 and INTTM2, respectively).
When TM1 and TM2 are set to interval timer operation, they can be used as registers to hold interval time.
CR10 and CR20 are set with an 8-bit memory manipulation instruction. They cannot be set with a 16-bit memory
manipulation instruction. When the compare register is used as an 8-bit timer/event counter, the 00H to FFH
values can be set. When the compare registers are used as 16-bit timer/event counter, the 0000H to FFFFH
values can be set.
RESET input makes CR10 and CR20 undefined.
Cautions 1. When using the compare registers as 16-bit timer/event counter, be sure to set data after
(2) 8-bit timer registers 1, 2 (TM1, TM2)
These are 8-bit registers to count count pulses.
When TM1 and TM2 are used in the 8-bit timer × 2-channel mode, they are read with an 8-bit memory manipulation
instruction. When TM1 and TM2 are used as 16-bit timer × 1-channel mode, 16-bit timer register (TMS) is read
with a 16-bit memory manipulation instruction.
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RESET input sets TM1 and TM2 to 00H.
9.3 8-Bit Timer/Event Counter Control Registers
The following four types of registers are used to control the 8-bit timer/event counter.
• Timer clock select register 1 (TCL1)
• 8-bit timer mode control register (TMC1)
• 8-bit timer output control register (TOC1)
• Port mode register 3 (PM3)
(1) Timer clock select register 1 (TCL1)
This register sets count clocks of 8-bit timer registers 1 and 2.
TCL1 is set with an 8-bit memory manipulation instruction.
RESET input sets TCL1 to 00H.
CHAPTER 9 8-BIT TIMER/EVENT COUNTER
stopping timer operation.
2. When the values of CR10 and CR20 posterior to alteration are less than the values of the
8-bit timer registers (TM1 and TM2), TM1 and TM2 keep on counting and resume counting
from 0 after an overflow. When the values of CR10 and CR20 posterior to alteration are
less than the values prior to alteration, the timer must be restarted after CR10 and CR20
are altered.
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