M16C30P_07 Datasheet, PDF (123/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
14. Timers
14.1.4 Pulse Width Modulation (PWM) Mode
In PWM mode, the timer outputs pulses of a given width in succession (see Table 14.5). The counter functions
as either 16-bit pulse width modulator or 8-bit pulse width modulator. Figure 14.12 shows TAiMR Register in
PWM Mode. Figures 14.13 and 14.14 show Example of 16-bit Pulse Width Modulator Operation and Example
of 8-bit Pulse Width Modulator Operation.
Table 14.5 Specifications in PWM Mode
Item
Count Source
Count Operation
16-bit PWM
8-bit PWM
Count Start Condition
Count Stop Condition
Interrupt Request
Generation Timing
TAiIN Pin Function
TAiOUT Pin Function
Read from Timer
Write to Timer
Specification
f1, f2, f8, f32, fC32
• Down-count (operating as an 8-bit or a 16-bit pulse width modulator)
• The timer reloads a new value at a rising edge of PWM pulse and continues
counting
• The timer is not affected by a trigger that occurs during counting
• High level width n / fj
n : set value of TAi register (i=o to 2)
• Cycle time (2¹⁶-1) / fj fixed fj: count source frequency (f1, f2, f8, f32, fC32)
• High level width n × (m+1) / fj n : set value of TAi register high-order address
• Cycle time (2⁸-1) × (m+1) / fj m : set value of TAi register low-order address
• TAiS bit of TABSR register is set to “1” (= start counting)
• The TAiS bit = 1 and external trigger input from the TAiIN pin
• The TAiS bit = 1 and one of the following external triggers occurs
• Timer B2 overflow or underflow,
Timer Aj (j=i-1, however, do not set when i=0) overflow or underflow,
Timer Ak (k=i+1, however, do not set when i=2) overflow or underflow
TAiS bit is set to “0” (= stop counting)
PWM pulse goes “L”
I/O port or trigger input
Pulse output
An indeterminate value is read by reading TAi register
• When not counting and until the 1st count source is input after counting start
Value written to TAi register is written to both reload register and counter
• When counting (after 1st count source input)
Value written to TAi register is written to only reload register
(Transferred to counter when reloaded next)
Rev.1.22 Mar 29, 2007 Page 107 of 291
REJ09B0179-0122