M16C30_02 Datasheet, PDF (78/178 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Timer A
Mitsubishi microcomputers
M16C / 30 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Timer A
Figure 1.14.3 shows the block diagram of timer A. Figures 1.14.4 to 1.14.6 show the timer A-related
registers.
Except in event counter mode, timers A0 through A2 all have the same function. Use the timer Ai mode
register (i = 0 to 2) bits 0 and 1 to choose the desired mode.
Timer A has the four operation modes listed as follows:
• Timer mode: The timer counts an internal count source.
• Event counter mode: The timer counts pulses from an external source or a timer overflow.
• One-shot timer mode: The timer stops counting when the count reaches “000016”.
• Pulse width modulation (PWM) mode: The timer outputs pulses of a given width.
Clock source
selection
f1
f8
f32
fC32
• Timer
• One shot
• PWM
Clock selection
• Timer
(gate function)
Data bus high-order bits
Data bus low-order bits
Low-order
8 bits
Reload register (16)
High-order
8 bits
Polarity
selection
TAiIN
(i = 0 to 2)
• Event counter
Clock selection
Count start flag
(Address 038016)
TB2 overflow
To external
TAj overflow
trigger circuit
(j = i – 1. Note, however, must not be set when i = 0)
Down count
TAk overflow
(k = i + 1. Note, however, must not be set when i = 2)
Up/down flag
(Address 038416)
Counter (16)
Up count/down count
Always down count except
in event counter mode
TAi
Timer A0
Timer A1
Timer A2
Addresses
038716 038616
038916 038816
038B16 038A16
TAj
Must not be set
Timer A0
Timer A1
TAk
Timer A1
Timer A2
Must not be set
TAiOUT
(i = 0 to 2)
Pulse output
Toggle flip-flop
Figure 1.14.3. Block diagram of timer A
Timer Ai mode register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
TAiMR(i=0 to 2)
Address
When reset
039616 to 039816 0016
Bit symbol
TMOD0
TMOD1
MR0
MR1
MR2
MR3
TCK0
TCK1
Bit name
Operation mode select bit
Function
b1 b0
0 0 : Timer mode
0 1 : Event counter mode
1 0 : One-shot timer mode
1 1 : Pulse width modulation
(PWM) mode
Function varies with each operation mode
Count source select bit
(Function varies with each operation mode)
RW
Figure 1.14.4. Timer A-related registers (1)
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