CHAPTER 8 8-BIT TIMERS H0 AND H1User’s Manual U16227EJ2V0UD1868.4 Operation of 8-Bit Timers H0 and H18.4.1 Operation as interval timer/square-wave outputWhen 8-bit timer counter Hn and compare register 0n (CMP0n) match, an interrupt request signal (INTTMHn) isgenerated and 8-bit timer counter Hn is cleared to 00H.Compare register 1n (CMP1n) is not used in interval timer mode. Since a match of 8-bit timer counter Hn and theCMP1n register is not detected even if the CMP1n register is set, timer output is not affected.By setting bit 0 (TOENn) of timer H mode register n (TMHMDn) to 1, a square wave of any frequency (duty = 50%)is output from TOHn.(1) UsageGenerates the INTTMHn signal repeatedly at the same interval.<1> Set each register.Figure 8-9. Register Setting During Interval Timer/Square-Wave Output Operation(i) Setting timer H mode register n (TMHMDn)0 0/1 0/1 0/1 0 0 0/1 0/1TMMDn0 TOLEVn TOENnCKSn1CKSn2TMHEnTMHMDnCKSn0 TMMDn1Timer output settingTimer output level inversion settingInterval timer mode settingCount clock (fCNT) selectionCount operation stopped(ii) CMP0n register setting• Compare value (N)<2> Count operation starts when TMHEn = 1.<3> When the values of 8-bit timer counter Hn and the CMP0n register match, the INTTMHn signal is generatedand 8-bit timer counter Hn is cleared to 00H.Interval time = (N +1)/fCNT<4> Subsequently, the INTTMHn signal is generated at the same interval. To stop the count operation, clearTMHEn to 0.Remark n = 0, 1
