MCMC68HC05L16 Freescale Semiconductor, Inc, MCMC68HC05L16 Datasheet - Page 66

• Manufacturer Part Number: MCMC68HC05L16
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Oscillators/Clock Distributions
7.5.6 Timebase Control Register 2
Read
Write
TBIF — Timebase Interrupt Flag
TBIE — Timebase Interrupt Enable
TBR1 and TBR0 — Timebase Interrupt Rate Select
RTBIF — Reset TBS Interrupt Flag
Bit 2 — Reserved
66
Anytime (Bits 3 and 0 are write-only bits and always read as logic 0.)
Anytime (Bit 7 is a read-only bit and write has no effect; bit 1 is 1-time write bit.)
The TBIF bit is set every timeout interval of the timebase counter. This read-only bit is cleared by
writing a logic 1 to the RTBIF bit. Reset clears the TBIF bit. The timebase interrupt period between
reset and the first TBIF depends on the time elapsed during reset, since the timebase divider is not
initialized on reset.
The TBIE bit enables the timebase interrupt capability. If TBIF = 1 and TBIE = 1, the timebase interrupt
is generated.
The TBR1 and TBR0 bits select one of four rates for the timebase interrupt period (see
TBS rate is also related to the COP timeout reset period. These bits are set to logic 1 on reset.
The RTBIF bit is a write-only bit and is always read as logic 0. Writing logic 1 to this bit clears the TBIF
bit and writing logic 0 to this bit has no effect.
This bit is not used and is always read as logic 0.
0 = Timebase interrupt disabled
1 = Timebase interrupt requested when TBIF = 1
TBR1
Address:
Reset:
0
0
1
1
Read:
Write:
TBCR2
TBR0
0
1
0
1
$0011
TBIF
Bit 7
0
Figure 7-6. Timebase Control Register 2 (TBCR2)
TBCLK ÷ 16,384
MC68HC05L16 • MC68HC705L16 Data Sheet, Rev. 4.1
TBCLK ÷ 4096
TBCLK ÷ 8192
TBCLK ÷ 128
Divide Ratio
= Unimplemented
Table 7-5. Timebase Interrupt Frequency
TBIE
6
0
TBR1
5
1
OSC = 4.0 M
7.63
3.81
1.91
244
TBR0
4
1
OSC = 4.1943 M
RTBIF
3
0
0
Frequency (Hz)
8.00
4.00
2.00
256
2
0
0
XOSC = 32.768 k
COPE
1
0
0
8.00
4.00
2.00
256
Freescale Semiconductor
COPC
Bit 0
0
0
Table
7-3). The