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RL78/G1A CHAPTER 6 TIMER ARRAY UNIT
R01UH0305EJ0200 Rev.2.00 221
Jul 04, 2013
6.4.2 Basic rules of 8-bit timer operation function (channels 1 and 3 only)
The 8-bit timer operation function makes it possible to use a 16-bit timer channel in a configuration consisting of two 8-
bit timer channels.
This function can only be used for channels 1 and 3, and there are several rules for using it.
The basic rules for this function are as follows:
(1) The 8-bit timer operation function applies only to channels 1 and 3.
(2) When using 8-bit timers, set the SPLIT bit of timer mode register mn (TMRmn) to 1.
(3) The higher 8 bits can be operated as the interval timer function.
(4) At the start of operation, the higher 8 bits output INTTMm1H/INTTMm3H (an interrupt) (which is the same
operation performed when MDmn0 is set to 1).
(5) The operation clock of the higher 8 bits is selected according to the CKSmn1 and CKSmn0 bits of the lower-bit
TMRmn register.
(6) For the higher 8 bits, the TSHm1/TSHm3 bit is manipulated to start channel operation and the TTHm1/TTHm3 bit
is manipulated to stop channel operation. The channel status can be checked using the TEHm1/TEHm3 bit.
(7) The lower 8 bits operate according to the TMRmn register settings. The following three functions support
operation of the lower 8 bits:
• Interval timer function
• External event counter function
• Delay count function
(8) For the lower 8 bits, the TSm1/TSm3 bit is manipulated to start channel operation and the TTm1/TTm3 bit is
manipulated to stop channel operation. The channel status can be checked using the TEm1/TEm3 bit.
(9) During 16-bit operation, manipulating the TSHm1, TSHm3, TTHm1, and TTHm3 bits is invalid. The TSm1, TSm3,
TTm1, and TTm3 bits are manipulated to operate channels 1 and 3. The TEHm3 and TEHm1 bits are not changed.
(10) For the 8-bit timer function, the simultaneous operation functions (one-shot pulse, PWM, and multiple PWM)
cannot be used.
Remark m: Unit number (m = 0), n: Channel number (n = 1, 3)