s908gz60cfa Freescale Semiconductor, Inc, s908gz60cfa Datasheet - Page 273

• Manufacturer Part Number: s908gz60cfa
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

18.8.2 TIM1 Counter Registers
The two read-only TIM1 counter registers contain the high and low bytes of the value in the TIM1 counter.
Reading the high byte (T1CNTH) latches the contents of the low byte (T1CNTL) into a buffer. Subsequent
reads of T1CNTH do not affect the latched T1CNTL value until T1CNTL is read. Reset clears the TIM1
counter registers. Setting the TIM1 reset bit (TRST) also clears the TIM1 counter registers.
18.8.3 TIM1 Counter Modulo Registers
The read/write TIM1 modulo registers contain the modulo value for the TIM1 counter. When the TIM1
counter reaches the modulo value, the overflow flag (TOF) becomes set, and the TIM1 counter resumes
counting from $0000 at the next timer clock. Writing to the high byte (T1MODH) inhibits the TOF bit and
overflow interrupts until the low byte (T1MODL) is written. Reset sets the TIM1 counter modulo registers.
Freescale Semiconductor
Address: $0021
Address: $0022
Address: $0023
Address: $0024
If you read T1CNTH during a break interrupt, be sure to unlatch T1CNTL
by reading T1CNTL before exiting the break interrupt. Otherwise, T1CNTL
retains the value latched during the break.
Reset the TIM1 counter before writing to the TIM1 counter modulo registers.
Reset:
Reset:
Reset:
Reset:
Read:
Read:
Read:
Read:
Write:
Write:
Write:
Write:
Figure 18-7. TIM1 Counter Modulo Registers (T1MODH:T1MODL)
MC68HC908GZ60 • MC68HC908GZ48 • MC68HC908GZ32 Data Sheet, Rev. 6
Figure 18-6. TIM1 Counter Registers (T1CNTH:T1CNTL)
Bit 15
Bit15
Bit 7
Bit 7
Bit 7
Bit 7
Bit 7
Bit7
0
0
1
1
T1CNTH
T1CNTL
= Unimplemented
T1MODH
T1MODL
Bit 14
Bit14
Bit 6
Bit6
6
0
6
0
6
1
6
1
Bit 13
Bit13
Bit 5
Bit5
5
0
5
0
5
1
5
1
NOTE
NOTE
Bit 12
Bit12
Bit 4
Bit4
4
0
4
0
4
1
4
1
Bit 11
Bit11
Bit 3
Bit3
3
0
3
0
3
1
3
1
Bit 10
Bit10
Bit 2
Bit2
2
0
2
0
2
1
2
1
Bit 9
Bit 1
Bit9
Bit1
1
0
1
0
1
1
1
1
Input/Output Registers
Bit 0
Bit 8
Bit 0
Bit 0
Bit 0
Bit 0
Bit8
Bit0
0
0
1
1
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