Datasheet

78K0/Ix2 CHAPTER 9 8-BIT TIMER H1
R01UH0010EJ0500 Rev.5.00 356
Feb 28, 2012
Figure 9-15. Carrier Generator Mode Operation Timing (3/3)
(c) Operation when CMP11 is changed
8-bit timer H1
count clock
CMP01
TMHE1
INTTMH1
Carrier clock
00H 01H N 00H 01H 01H
M
00H N 00H L 00H
<1>
<3>’
<4>
<3>
<2>
CMP11
<5>
M
N
L
M (L)
8-bit timer counter
H1 count value
<1> When TMHE1 = 1 is set, the 8-bit timer H1 starts a count operation. At that time, the carrier clock remains default.
<2> When the count value of the 8-bit timer counter H1 matches the value of the CMP01 register, the INTTMH1
signal is output, the carrier signal is inverted, and the timer counter is cleared to 00H. At the same time, the
compare register whose value is to be compared with that of the 8-bit timer counter H1 is changed from the
CMP01 register to the CMP11 register.
<3> The CMP11 register is asynchronous to the count clock, and its value can be changed while the 8-bit timer H1 is
operating. The new value (L) to which the value of the register is to be changed is latched. When the count
value of the 8-bit timer counter H1 matches the value (M) of the CMP11 register before the change, the CMP11
register is changed (<3>’).
However, it takes three count clocks or more since the value of the CMP11 register has been changed until the
value is transferred to the register. Even if a match signal is generated before the duration of three count clocks
elapses, the new value is not transferred to the register.
<4> When the count value of 8-bit timer counter H1 matches the value (M) of the CMP11 register before the change,
the INTTMH1 signal is output, the carrier signal is inverted, and the timer counter is cleared to 00H. At the same
time, the compare register whose value is to be compared with that of the 8-bit timer counter H1 is changed from
the CMP11 register to the CMP01 register.
<5> The timing at which the count value of the 8-bit timer counter H1 and the CMP11 register value match again is
indicated by the value after the change (L).