M16C1N Datasheet, PDF (117/238 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/10 SERIES

M16C/1N Group
12. Timers
12.5 Timer C
Timer C is a 16-bit free-running timer. The Timer C uses an edge input to TCIN pin or the output of 256
fRING divisions as trigger to latch the timer count value and generates an interrupt request. The TCIN
input has a digital filter and this prevents an error caused by noise or so on from occurring.
Figure 12.31 shows the block diagram of Timer C. Table 12.14 shows Timer C specifications. Figure
12.32 shows Timer C-related registers. Figure 12.33 shows an operation example of Timer C and timer
measurement register.
Data bus
Address 009D16 Address 009C16
Upper 8 bits
Lower 8 bits
Time measurement register (16)
Timer C clock
TCIN
select bit
f1
f8
f32
Digital
"0"
filter
Upper 8 bits
Lower 8 bits
Timer C counter (16)
Address 009116
Address 009016
Edge detection
f1
"1"
f8
Time measurement
f32
Digital filter clock
input source
switching bit
select bit
Timer C overflow interrupt
Reload signal
TCIN interrupt
On-chip oscillation 1/256
Figure 12.31 Block diagram of Timer C
Table 12.14 Specifications of Timer C
Item
Specification
Count source
f1, f8, f32
Count operation
• Up count
• Transfer counter value to time measurement register at active edge of
measurement pulse
• When timer C stops counting, the value of timer C is reset to "000016".
Count start condition
• Time measurement control bit is set (=1)
Counter stop condition
• Time measurement control bit is reset (=0)
Interrupt request generation timing • When active edge of measurement pulse is input [TCIN interrupt]
• When the time underflows [Timer C interrput]
TCIN pin function
Measurement pulse input
Count value reset timing When time measurement control bit is reset (=0)
Read from timer (Note 1) • Count value can be read out by reading Timer C.
• Count value at measurement pulse active edge input can be read out by reading time
measurement register.
Write to timer
Cannot write to Timer C and time measurement register
Select function
• Measurement pulse active edge: selectable (rising edge/falling edge/both edges)
• Measurement pulse: selectable (input from TCIN pin/256 divisions of fRING)
• Digital filter sampling frequency: selectable (f1/f8/f32)
Note 1: The Timer C and the timer measurement register must be read in word-size.
Rev.1.00 Oct 20, 2004 page 105 of 222
REJ09B0007-0100Z