Freescale Semiconductor HCS08 Series, Reference Manual

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Chapter 14 Timer/Pulse-Width Modulator (S08TPMV3)
MC9S08JS16 MCU Series Reference Manual, Rev. 4
Freescale Semiconductor 219
14.3.1 Migrating from TPMV1
In addition to Section 14.3, “TPMV3 Differences from Previous Versions ,” keep in mind the following
considerations when migrating from a device that uses TPMV1.
• You can write to the Channel Value register (TPMCnV) when the timer is not in input capture mode
for TPMV2, not TPMV3.
• In edge- or center- aligned modes, the Channel Value register (TPMCnV) registers only update
when the timer changes from TPMMOD-1 to TPMMOD, or in the case of a free running timer
from 0xFFFE to 0xFFFF.
• Also, when configuring the TPM modules, it is best to write to TPMSC before TPMCnV as a write
to TPMxSC resets the coherency mechanism on the TPMCnV registers.
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For more information, refer to Section 14.6.2.4, “Center-Aligned PWM Mode .” [SE110-TPM case 4]
Table 14-2. Migrating to TPMV3 Considerations
When... Action / Best Practice
Writing to the Channel Value Register (TPMCnV)
register... Timer must be in Input Capture mode.
Updating the Channel Value Register (TPMCnV)
register in edge-aligned or center-aligned modes... Only occurs when the timer changes from
TPMMOD – 1 to TPMMOD (or in the case of a free
running timer, from 0xFFFE to 0xFFFF).
Reseting the coherency mechanism for the
Channel Value Register (TPMCnV) register... Write to TPMSC.
Configuring the TPM modules... Write first to TPMSC and then to TPMCnV register.