M16C30L Datasheet, PDF (90/166 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Timer B
Mitsubishi microcomputers
M16C / 30L Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(1) Timer mode
In this mode, the timer counts an internally generated count source. (See Table 1.14.6.) Figure 1.14.17
shows the timer Bi mode register in timer mode.
Table 1.14.6. Timer specifications in timer mode
Item
Specification
Count source
f1, f8, f32, fC32
Count operation
• Counts down
• 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 The timer underflows
TBiIN pin function
Programmable I/O port
Read from timer
Count value is read out by reading timer Bi register
Write to timer
• When counting stopped
When a value is written to timer Bi register, it is written to both reload register and counter
• When counting in progress
When a value is written to timer Bi register, it is written to only reload register
(Transferred to counter at next reload time)
Timer Bi mode register
b7 b6 b5 b4 b3 b2 b1 b0
00
Symbol
TBiMR(i=1, 2)
Address
039C16, 039D16
When reset
00XX00002
Bit symbol
TMOD0
TMOD1
MR0
MR1
Bit name
Function
Operation mode select bit
b1 b0
0 0 : Timer mode
Invalid in timer mode
Can be “0” or “1”
Nothing is assiigned.
In an attempt to write to this bit, write “0”. The value, if read,
turns out to be indeterminate.
MR3
TCK0
TCK1
Invalid in timer mode.
In an attempt to write to this bit, write “0”. The value, if read in
timer mode, turns out to be indeterminate.
Count source select bit
b7 b6
0 0 : f1
0 1 : f8
1 0 : f32
1 1 : fC32
RW
Figure 1.14.17. Timer Bi mode register in timer mode
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