mc68hc908lj24 Freescale Semiconductor, Inc, mc68hc908lj24 Datasheet - Page 210

• Manufacturer Part Number: mc68hc908lj24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Timer Interface Module (TIM)
11.10.2 TIM Counter Registers
Data Sheet
210
NOTE:
Address: T1CNTH, $0021 and T2CNTH, $002C
PS[2:0] — Prescaler Select Bits
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:
Read:
Write:
These read/write bits select one of the seven prescaler outputs as the
input to the TIM counter as
PS[2:0] bits.
PS2
0
0
0
0
1
1
1
1
Bit 15
Figure 11-5. TIM Counter Registers High (TCNTH)
Bit 7
0
Timer Interface Module (TIM)
PS1
0
0
1
1
0
0
1
1
= Unimplemented
14
6
0
Table 11-2. Prescaler Selection
PS0
0
1
0
1
0
1
0
1
13
5
0
Table 11-2
12
4
0
Internal bus clock ÷ 1
Internal bus clock ÷ 2
Internal bus clock ÷ 4
Internal bus clock ÷ 8
Internal bus clock ÷ 16
Internal bus clock ÷ 32
Internal bus clock ÷ 64
MC68HC908LJ24/LK24 — Rev. 2.1
shows. Reset clears the
11
3
0
TIM Clock Source
TCLK
Freescale Semiconductor
10
2
0
9
1
0
Bit 0
Bit 8
0