MC68HC908JK8CP Freescale Semiconductor, MC68HC908JK8CP Datasheet - Page 115

• Manufacturer Part Number: MC68HC908JK8CP
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC908JK8CP

• Cpu Family: HC08
• Device Core Size: 8b
• Frequency (max): 8MHz
• Interface Type: SCI
• Program Memory Type: Flash
• Program Memory Size: 8KB
• Total Internal Ram Size: 256Byte
• # I/os (max): 15
• Number Of Timers - General Purpose: 4
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 13-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 20
• Package Type: PDIP
• Lead Free Status / Rohs Status: Not Compliant

TSTOP — TIM Stop Bit
TRST — TIM Reset Bit
PS[2:0] — Prescaler Select Bits
8.9.2 TIM Counter Registers
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.
Freescale Semiconductor
This read/write bit stops the TIM counter. Counting resumes when TSTOP is cleared. Reset sets the
TSTOP bit, stopping the TIM counter until software clears the TSTOP bit.
Setting this write-only bit resets the TIM counter and the TIM prescaler. Setting TRST has no effect on
any other registers. Counting resumes from $0000. TRST is cleared automatically after the TIM
counter is reset and always reads as logic 0. Reset clears the TRST bit.
These read/write bits select one of the seven prescaler outputs as the input to the TIM counter as
Table 8-2
1 = TIM counter stopped
0 = TIM counter active
1 = Prescaler and TIM counter cleared
0 = No effect
shows. Reset clears the PS[2:0] bits.
Do not set the TSTOP bit before entering wait mode if the TIM is required
to exit wait mode.
Setting the TSTOP and TRST bits simultaneously stops the TIM counter at
a value of $0000.
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.
PS2
MC68HC908JL8/JK8 • MC68HC08JL8/JK8 • MC68HC908KL8 Data Sheet, Rev. 3.1
0
0
0
0
1
1
1
1
PS1
0
0
1
1
0
0
1
1
Table 8-2. Prescaler Selection
PS0
0
1
0
1
0
1
0
1
NOTE
NOTE
NOTE
T2CLK (for TIM2 only)
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
TIM Clock Source
I/O Registers
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