MC68HC08GZ32 Datasheet, PDF (270/320 Pages) Freescale Semiconductor, Inc – Microcontrollers

Timer Interface Module (TIM2)
19.8.2 TIM2 Counter Registers
The two read-only TIM2 counter registers contain the high and low bytes of the value in the TIM2 counter.
Reading the high byte (T2CNTH) latches the contents of the low byte (T2CNTL) into a buffer. Subsequent
reads of T2CNTH do not affect the latched T2CNTL value until T2CNTL is read. Reset clears the TIM2
counter registers. Setting the TIM2 reset bit (TRST) also clears the TIM2 counter registers.
NOTE
If T2CNTH is read during a break interrupt, be sure to unlatch T2CNTL by
reading T2CNTL before exiting the break interrupt. Otherwise, T2CNTL
retains the value latched during the break.
Register Name and Address
T2CNTH — $002C
Bit 7
6
5
4
3
2
1
Bit 0
Read: BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
Write:
Reset: 0
0
0
0
0
0
0
0
Register Name and Address
T2CNTL — $002D
Bit 7
6
5
4
3
2
1
Bit 0
Read: BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Write:
Reset: 0
0
0
0
0
0
0
0
= Unimplemented
Figure 19-6. TIM2 Counter Registers (T2CNTH and T2CNTL)
19.8.3 TIM2 Counter Modulo Registers
The read/write TIM2 modulo registers contain the modulo value for the TIM2 counter. When the TIM2
counter reaches the modulo value, the overflow flag (TOF) becomes set, and the TIM2 counter resumes
counting from $0000 at the next timer clock. Writing to the high byte (T2MODH) inhibits the TOF bit and
overflow interrupts until the low byte (T2MODL) is written. Reset sets the TIM2 counter modulo registers.
Register Name and Address
T2MODH — $002E
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10
BIT 9
BIT 8
Write:
Reset: 1
1
1
1
1
1
1
1
Register Name and Address
T2MODL — $002F
Bit 7
6
5
4
3
2
1
Bit 0
Read:
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Write:
Reset: 1
1
1
1
1
1
1
1
Figure 19-7. TIM2 Counter Modulo Registers (T2MODH and T2MODL)
NOTE
Reset the TIM2 counter before writing to the TIM2 counter modulo registers.
MC68HC08GZ32 Data Sheet, Rev. 3
270
Freescale Semiconductor