Base Timer - Renesas M16C/29 Series Hardware Manual

M16C/29 Group

13.1 Base Timer

The base timer counts an internally generated count source with free-running.
Table 13.1.1 lists specifications of the base timer. Table 13.1.2 shows registers associated with the base
timer. Figure 13.1.1 shows a block diagram of the base timer. Figure 13.1.2 shows an example of the base
timer in counter increment mode. Figure 13.1.3 shows an example of the base timer in counter increment/
decrement mode. Figure 13.1.4 shows an example of two-phase pulse signal processing mode.
Table 13.1.1. Base Timer Specifications
Item
Count source(f )
BT1
Counting operation
Count start condition
Count stop condition
Base timer reset condition
Value for base timer reset
Interrupt request
Read from timer
Write to timer
Selectable function
Rev.1.00 Nov 01,2004
REJ09B0101-0100Z
f or f divided by (n+1) ,
1 2
n: The DIV7 to DIV0 bits in the G1DV register determines.
In f and two pulse input when n=0, a count source is not divided
1
The base timer increments the counter
The base timer increments/decrements the counter (see the selectable function)
Two-phase pulse processing (see the selectable function)
• The base timer starts counting when the BTS bit in the G1BCR1 register is set
to "1"
The BTS bit in the G1BCR1 register is set to "0" (base timer reset)
(1) Value of the base timer matches value of the G1BTRR register
(2) Value of the base timer matches value of G1PO0 register.
(3) Apply a low-level signal ("L") to external interrupt pin,INT1 pin
"0000 "
16
The base timer interrupt request is asserten:
(1) At bit 14 or bit 15 is overflow of the base timer
(2) Base timer value matches the base timer reset register, and the base
timer reset is enable (See Figure 13.1.1.)
• While the base timer is running,the G1BT register indicates a counter value
• When the base timer is reset, a counter value is indeterminate
When a value is written while the base timer is running, the value written is
counted first. No value can be written while the base timer is reset.
• Counter increment/decrement mode
The base timer starts counting in increment mode until reaching the
maximum count value. Then the base timer starts in decrement mode until
reaching next 0000
• Two-phase pulse processing mode.
Two-phase pulses from P8
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13. Timer S (Input Capture / Output Compare)
Specification
two pulse input divided by (n+1)
. (See Figure 13.1.3.)
16
and P8
0
P8
0
P8
1
The timer increments
a counter on all edges
pins are counted (See Figure 13.1.4.)
1
The timer decrements
a counter on all edges
n=0 to 255