NEC 78K0/KD1 Series User Manual page 200

(b) Operation when CMP01 = 1, CMP11 = M (operation when carrier clock phase is asynchronous to NRZ1 phase)
8-bit timer H1
count clock
8-bit timer counter
H1 count value
CMP01
CMP11
TMHE1
INTTMH1
Carrier clock
8-bit timer 51
count clock
TM51 count value
CR51
TCE51
INTTM51
NRZB1
NRZ1
Carrier clock
TOH1
<1> When TMHE1 = 0 and TCE51 = 0, 8-bit timer H1 operation is stopped.
<2> When TMHE1 = 1 is set, 8-bit timer H1 starts a count operation. At that time, the carrier clock is held at the
inactive level.
<3> When the count value of 8-bit timer counter H1 matches the CMP01 register value, the first INTTMH1 signal
is generated, the carrier clock signal is inverted, and the compare register to be compared with 8-bit timer
counter H1 is switched from the CMP01 register to the CMP11 register. 8-bit timer counter H1 is cleared to
00H.
<4> When the count value of 8-bit timer counter H1 matches the CMP11 register value, the INTTMH1 signal is
generated, the carrier clock signal is inverted, and the compare register to be compared with 8-bit timer
counter H1 is switched from the CMP11 register to the CMP01 register. 8-bit timer counter H1 is cleared to
00H. By performing procedures <3> and <4> repeatedly, a carrier clock with duty ratio fixed to other than
50% is generated.
<5> When the INTTM51 signal is generated, it is synchronized with 8-bit timer H1 count clock and output as the
INTTM5H1 signal.
<6> When the carrier clock phase becomes asynchronous to the NRZ1 bit phase, a carrier signal is output at the
first rising edge of the carrier clock if NRZ1 is set to 1.
<7> When NRZ1 = 0, the TOH1 output is held at the high level and is not changed to low level while the carrier
clock is high level (from <6> and <7>, the high-level width of the carrier clock waveform is guaranteed).
200
CHAPTER 8 8-BIT TIMERS H0 AND H1
Figure 8-13. Carrier Generator Mode Operation Timing (2/3)
00H N 00H 01H
<3>
<1> <2>
00H 01H L 00H 01H
<5>
0 1
0
Preliminary User's Manual U16315EJ1V0UD
M 00H N 00H 01H
N
M
<4>
L 00H 01H L 00H 01H
L
0 1
<6>
1 0
<7>
M 00H N 00H
L 00H 01H
0
1 0