UPD78F9234MC-5A4-A Datasheet, PDF (144/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 8 8-BIT TIMER H1
8.4 Operation of 8-bit Timer H1
8.4.1 Operation as interval timer/square-wave output
When 8-bit timer counter H1 and compare register 01 (CMP01) match, an interrupt request signal (INTTMH1) is
generated and 8-bit timer counter H1 is cleared to 00H.
Compare register 11 (CMP11) is not used in interval timer mode. Since a match of 8-bit timer counter H1 and the
CMP11 register is not detected even if the CMP11 register is set, timer output is not affected.
By setting bit 0 (TOEN1) of timer H mode register 1 (TMHMD1) to 1, a square wave of any frequency (duty = 50%)
is output from TOH1.
(1) Usage
Generates the INTTMH1 signal repeatedly at the same interval.
<1> Set each register.
Figure 8-6. Register Setting During Interval Timer/Square-Wave Output Operation
(i) Setting timer H mode register 1 (TMHMD1)
TMHE1
TMHMD1
0
CKS12 CKS11
0/1
0/1
CKS10 TMMD11 TMMD10 TOLEV1 TOEN1
0/1
0
0
0/1
0/1
Timer output setting
Timer output level inversion setting
Interval timer mode setting
Count clock (fCNT) selection
Count operation stopped
(ii) CMP01 register setting
• Compare value (N)
<2> Count operation starts when TMHE1 = 1.
<3> When the values of 8-bit timer counter H1 and the CMP01 register match, the INTTMH1 signal is generated
and 8-bit timer counter H1 is cleared to 00H.
Interval time = (N +1)/fCNT
<4> Subsequently, the INTTMH1 signal is generated at the same interval. To stop the count operation, clear
TMHE1 to 0.
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User’s Manual U17446EJ5V0UD