mc68hc908rk2 Freescale Semiconductor, Inc, mc68hc908rk2 Datasheet - Page 210

• Manufacturer Part Number: mc68hc908rk2
• Description: Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface Module (TIM)
15.9.2 TIM Counter Registers
Advance Information
210
NOTE:
Register Name and Address: TCNTH—$0021
Register Name and Address: TCNTL—$0022
The two read-only TIM counter registers contain the high and low bytes
of the value in the TIM counter. Reading the high byte (TCNTH) latches
the contents of the low byte (TCNTL) into a buffer. Subsequent reads of
TCNTH do not affect the latched TCNTL value until TCNTL is read.
Reset clears the TIM counter registers. Setting the TIM reset bit (TRST)
also clears the TIM counter registers
If you read TCNTH during a break interrupt, be sure to unlatch TCNTL
by reading TCNTL before exiting the break interrupt. Otherwise, TCNTL
retains the value latched during the break.
Reset:
Reset:
Read:
Read:
Write:
Write:
Figure 15-5. TIM Counter Registers (TCNTH and TCNTL)
Bit 15
Bit 7
Bit 7
Bit 7
0
0
Timer Interface Module (TIM)
PS2–PS0
000
001
010
100
101
011
110
111
= Unimplemented
14
6
0
6
6
0
Table 15-2. Prescaler Selection
13
5
0
5
5
0
12
Internal bus clock
Internal bus clock
Internal bus clock
4
0
4
4
0
Internal bus clock
Internal bus clock
Internal bus clock
Internal bus clock 1
TIM Clock Source
TCLK
11
3
0
3
3
0
MC68HC908RK2
10
0
0
2
2
2
16
32
64
2
8
4
0
0
1
9
1
1
MOTOROLA
—
Rev. 4.0
Bit 0
Bit 8
Bit 0
Bit 0
0
0