Chapter 16 Timer/PWM Module (S08TPMV3)
MC9S08DZ128 Series Data Sheet, Rev. 1
Freescale Semiconductor
377
BDM mode returns the latched value of TPMxCNTH:L from the read buffer instead of the
frozen TPM counter value.
— This read coherency mechanism is cleared in TPM v3 in BDM mode if there is a write to
TPMxSC, TPMxCNTH or TPMxCNTL. Instead, in these conditions the TPM v2 does not clear
this read coherency mechanism.
— In TPM v3, any read of TPMxCnVH:L registers during BDM mode returns the value of the
TPMxCnVH:L register. In TPM v2, if only one byte of the TPMxCnVH:L registers was read
before the BDM mode became active, then any read of TPMxCnVH:L registers during BDM
mode returns the latched value of TPMxCNTH:L from the read buffer instead of the value in
the TPMxCnVH:L registers.
— This read coherency mechanism is cleared in TPM v3 in BDM mode if there is a write to
TPMxCnSC. Instead, in this condition the TPM v2 does not clear this read coherency
mechanism.
4. Write to TPMxCnVH:L registers
In this mode the TPM v3 does not allow the writes to TPMxCnVH:L registers. Instead, the
TPM v2 allows these writes.
In this mode and if (CLKSB:CLKSA not = 0:0), the TPM v3 updates the TPMxCnVH:L
registers with the value of their write buffer at the next change of the TPM counter (end of the
prescaler counting) after the second byte is written. Instead, the TPM v2 always updates these
registers when their second byte is written.
In this mode and if (CLKSB:CLKSA not = 00), the TPM v3 updates the TPMxCnVH:L
registers with the value of their write buffer after that the both bytes were written and when the
TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). If the TPM counter is
a free-running counter, then this update is made when the TPM counter changes from $FFFE
to $FFFF. Instead, the TPM v2 makes this update after that the both bytes were written and
when the TPM counter changes from TPMxMODH:L to $0000.
In this mode and if (CLKSB:CLKSA not = 00), the TPM v3 updates the TPMxCnVH:L
registers with the value of their write buffer after that the both bytes were written and when the
TPM counter changes from (TPMxMODH:L - 1) to (TPMxMODH:L). If the TPM counter is
a free-running counter, then this update is made when the TPM counter changes from $FFFE
to $FFFF. Instead, the TPM v2 makes this update after that the both bytes were written and
when the TPM counter changes from TPMxMODH:L to (TPMxMODH:L - 1).
— TPMxCnVH:L = TPMxMODH:L [SE110-TPM case 1]
In this case, the TPM v3 produces 100% duty cycle. Instead, the TPM v2 produces 0% duty
cycle.