tmp89fm42 TOSHIBA Semiconductor CORPORATION, tmp89fm42 Datasheet - Page 152

• Manufacturer Part Number: tmp89fm42
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

12.1 Time Base Timer
12. Time Base Timer (TBT)
RA001
12.1.3 Functions
Note 3: TBTCR<TBTCK> should be set when TBTCR<TBTEN> is "0".
Note 4: When SYSCR1<DV9CK> is "1" in the NORMAL 1/2 or IDLE1/2 mode, the interrupt request is subject to some fluctuations
Note 5: Bits 7 to 4 of TBTCR are read as "0".
be changed when TBTCR<TBTEN> is "0". Otherwise, the INTTBT interrupt request is generated at unex-
pected timing.
clock. When TBTCR<TBTEN> is cleared to "0", no interrupt request signal will occur.
interrupt request is enabled. Therefore, the period from when the time TBTCR<TBTEN> is set to "1" to the
time when the first interrupt request occurs is shorter than the frequency period set at TBTCR<TBTCK>.
mode, The interrupt request will not occur at the expected timing due to synchronization of the gear clock
(fcgck) and the low-frequency clock (fs). It is recommened that the operation mode is changed when
TBTCR<TBTEN> is "0".
Table 12-1 Time Base Timer Interrupt Frequency (Example: when fcgck = 10.0 MHz and fs =
Select the source clock frequency for the time base timer by TBTCR<TBTCK>. TBTCR<TBTCK> should
Setting TBTCR<TBTEN> to "1" causes interrupt request signals to occur at the falling edge of the source
When the operation is changed to the STOP mode, TBTCR<TBTEN> is cleared to "0".
The source clock of the time base timer operates regardless of the TBTCR<TBTEN> value.
A time base timer interrupt is generated at the first falling edge of the source clock after a time base timer
When the operation is changed from NORMAL mode to SLOW mode or from SLOW mode to NORMAL
to synchronize fs and fcgck.
Example: Set the time base timer interrupt frequency to fcgck/2
TBTCK
000
001
010
011
100
101
110
111
32.768 kHz)
TBTCR<TBTEN>
INTTBT interrupt
request
Source clock
NORMAL1/2, IDLE1/2 mode
Figure 12-2 Time Base Timer Interrupt
DV9CK = 0
1220.70
2441.41
4882.81
9765.63
39062.5
305.18
2.38
9.54
Time base timer enable
Time base timer interrupt frequency [Hz]
Page 138
NORMAL1/2, IDLE1/2 mode
Interrupt period
DV9CK = 1
Reserved
1024
2048
4096
128
512
1
4
15
[Hz] and enable interrupts.
SLOW1/2, SLEEP1 mode
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
1
4
TMP89FM42