M16C User Manual.pdf

Counter content (hex)Timer BMitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTER2.3.2 Operation of Timer B (timer mode)In timer mode, choose functions from those listed in Table 2.3.1. Operations of the circled items aredescribed below. Figure 2.3.4 shows the operation timing, and Figure 2.3.5 shows the set-up procedure.Table 2.3.1. Choosed functionsItemSet-upCount sourceOInternal count source (f1 / f8 / f32 / fc32)Operation(1) Setting the count start flag to “1” causes the counter to perform a down count on the countsource.(2) If an underflow occurs, the content of the reload register is reloaded, and the counter continuescounting. At this time, the timer Bi interrupt request bit goes to “1”.(3) Setting the count start flag to “0” causes the counter to hold its value and to stop.n = reload register contentFFFF16(1) Start count(2) Underflow (3) Stop countnStart countagain000016TimeSet to “1” by softwareCleared to “0” bysoftwareSet to “1” by softwareCount start flagTimer Bi interruptrequest bit“1”“0”“1”“0”Cleared to “0” when interrupt request is accepted, or cleared by softwareFigure 2.3.4. Operation timing of timer mode316