mc9s08dn60 Freescale Semiconductor, Inc, mc9s08dn60 Datasheet - Page 269

• Manufacturer Part Number: mc9s08dn60
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

15.3.2
The two read-only TPM counter registers contain the high and low bytes of the value in the TPM counter.
Reading either byte (TPMxCNTH or TPMxCNTL) latches the contents of both bytes into a buffer where
they remain latched until the other half is read. This allows coherent 16-bit reads in either big-endian or
little-endian order which makes this more friendly to various compiler implementations. The coherency
mechanism is automatically restarted by an MCU reset or any write to the timer status/control register
(TPMxSC).
Reset clears the TPM counter registers. Writing any value to TPMxCNTH or TPMxCNTL also clears the
TPM counter (TPMxCNTH:TPMxCNTL) and resets the coherency mechanism, regardless of the data
involved in the write.
Freescale Semiconductor
Reset
W
R
Bit 15
TPM-Counter Registers (TPMxCNTH:TPMxCNTL)
0
7
14
0
6
Figure 15-8. TPM Counter Register High (TPMxCNTH)
CLKSB:CLKSA
PS2:PS1:PS0
000
001
010
011
100
101
110
111
Table 15-3. TPM-Clock-Source Selection
00
01
10
11
Table 15-4. Prescale Factor Selection
Any write to TPMxCNTH clears the 16-bit counter
MC9S08DN60 Series Data Sheet, Rev 2
13
5
0
No clock selected (TPM counter disable)
TPM Clock Source to Prescaler Input
TPM Clock Source Divided-by
12
0
4
Fixed system clock
External source
Bus rate clock
128
16
32
64
1
2
4
8
11
0
3
Chapter 15 Timer/PWM Module (S08TPMV3)
10
0
2
1
9
0
Bit 8
0
0
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