NEC 78K0 User Manual page 250

(3) Usage
Outputs an arbitrary carrier clock from the TOH1 pin.
<1> Set each register.
(i) Setting 8-bit timer H mode register 1 (TMHMD1)
TMHE1 CKS12
TMHMD1 0 0/1
(ii) CMP01 register setting
• Compare value
(iii) CMP11 register setting
• Compare value
(iv) TMCYC1 register setting
• RMC1 = 1 ... Remote control output enable bit
• NRZB1 = 0/1 ... carrier output enable bit
(v) TCL51 and TMC51 register setting
• See 8.3 Registers Controlling 8-Bit Timer/Event Counters 50 and 51.
<2> When TMHE1 = 1, 8-bit timer H1 starts counting.
<3> When TCE51 of 8-bit timer mode control register 51 (TMC51) is set to 1, 8-bit timer/event counter 51 starts
counting.
<4> After the count operation is enabled, the first compare register to be compared is the CMP01 register.
When the count value of 8-bit timer counter H1 and the CMP01 register value match, the INTTMH1 signal
is generated, 8-bit timer counter H1 is cleared, and at the same time, the compare register to be compared
with 8-bit timer counter H1 is switched from the CMP01 register to the CMP11 register.
<5> When the count value of 8-bit timer counter H1 and the CMP11 register value match, the INTTMH1 signal
is generated, 8-bit timer counter H1 is cleared, and at the same time, the compare register to be compared
with 8-bit timer counter H1 is switched from the CMP11 register to the CMP01 register.
<6> By performing procedures <4> and <5> repeatedly, a carrier clock is generated.
<7> The INTTM51 signal is synchronized with count clock of 8-bit timer H1 and output as the INTTM5H1 signal.
The INTTM5H1 signal becomes the data transfer signal for the NRZB1 bit, and the NRZB1 bit value is
transferred to the NRZ1 bit.
<8> When the NRZ1 bit is high level, a carrier clock is output from the TOH1 pin.
<9> By performing the procedures above, an arbitrary carrier clock is obtained. To stop the count operation,
clear TMHE1 to 0.
250
CHAPTER 9 8-BIT TIMERS H0 AND H1
Figure 9-14. Register Setting in Carrier Generator Mode
CKS11 CKS10 TMMD11
0/1 0/1 0
User's Manual U15947EJ2V0UD
TMMD10 TOLEV1 TOEN1
1 0/1 0/1
*
Timer output enabled
Timer output level inversion setting
Carrier generator mode selection
Count clock (f ) selection
CNT
Count operation stopped