Rev. 1.0, 02/00, page 250 of 1141
Bit 3
Selection of the Clock Source and Prescaler (TMA3): This bit works to select the PSS
or PSW as the clock source for the Timer A.
Bit 3
TMA3
Description
0
Selects the PSS as the clock source for the Timer A
(Initial value)
1
Selects the PSW as the clock source for the Timer A
Bits 2 to 0
Clock Selection (TMA2 to TMA0): These bits work to select the clock to input to
the TCA. In combination with the TMA3 bit, the choices are as follows:
Bit 3
Bit 2
Bit 1
Bit 0
TMA3
TMA2
TMA1
TMA0
Prescaler Division Ratio (Interval Timer)
or Overflow Cycle (Time Base)
Operation
Mode
0
PSS,
φ
/16384 (Initial value)
0
1
PSS,
φ
/8192
0
PSS,
φ
/4096
0
1
1
PSS,
φ
/1024
0
PSS,
φ
/512
0
1
PSS,
φ
/256
0
PSS,
φ
/64
0
1
1
1
PSS,
φ
/16
Interval
timer mode
0
1s
0
1
0.5s
0
0.25s
0
1
1
0.03125s
0
0
1
0
1
1
1
1
Works to clear the PSW and TCA to H'00
Clock time
base mode
Note:
φ
= f osc