M16C26 Datasheet, PDF (87/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

Udenvdeelropment
Timer A
Preliminary Specifications Rev. 0.9
Specifications in this manual are tentative and subject to change. _{M16C/26 Group}
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.12.1.) Figure 1.12.7
shows the timer Ai mode register in timer mode.
Table 1.12.1. Specifications of timer mode
Item
Specification
Count source
f1, f2, f8, f32, fC32
Count operation
• Down count
• When the timer underflows, it reloads the reload register contents before continuing counting
Divide ratio
1/(n+1)
n : Set value
Count start condition Count start flag is set (= 1)
Count stop condition Count start flag is reset (= 0)
Interrupt request generation timing When the timer underflows
TAiIN pin function
Programmable I/O port or gate input
TAiOUT pin function
Programmable I/O port or pulse output
Read from timer
Count value can be read out by reading timer Ai register
Write to timer
• When counting stopped
When a value is written to timer Ai register, it is written to both reload register and counter
• When counting in progress
When a value is written to timer Ai register, it is written to only reload register
(Transferred to counter at next reload time)
Select function
• Gate function
Counting can be started and stopped by the TAiIN pin’s input signal
• Pulse output function
Each time the timer underflows, the TAiOUT pin’s polarity is reversed
Timer Ai mode register
b7 b6 b5 b4 b3 b2 b1 b0
0
00
Symbol
TAiMR(i=0 to 4)
Address
When reset
039616 to 039A16 0016
Bit symbol
Bit name
Function
RW
TMOD0
TMOD1
MR0
Operation mode
select bit
Pulse output function
select bit
MR1
Gate function select bit
MR2
b1 b0
0 0 : Timer mode
0 : Pulse is not output
(TAiOUT pin is a normal port pin)
1 : Pulse is output (Note 1)
(TAiOUT pin is a pulse output pin)
b4 b3
0 X (Note 2): Gate function not available
(TAiIN pin is a normal port pin)
1 0 : Timer counts only when TAiIN pin is
held L (Note 3)
1 1 : Timer counts only when TAiIN pin is
held H (Note 3)
MR3
0 (Must always be 0 in timer mode)
TCK0
TCK1
Count source select bit
b7 b6
0 0 : f1 or f2
0 1 : f8
1 0 : f32
1 1 : fC32
Note 1: The settings of the corresponding port register and port direction register
are invalid.
Note 2: The bit can be 0 or 1 .
Note 3: Set the corresponding port direction register to 0 .
Figure 1.12.7. Timer Ai mode register in timer mode
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