MC9S08AW60 FREESCALE [Freescale Semiconductor, Inc], MC9S08AW60 Datasheet - Page 170

• Manufacturer Part Number: MC9S08AW60
• Description: Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 10 Timer/Pulse-Width Modulator (S08TPMV2)
Freescale-provided equate or header file is used to translate these names into the appropriate absolute
addresses.
Some MCU systems have more than one TPM, so register names include placeholder characters to identify
which TPM and which channel is being referenced. For example, TPMxCnSC refers to timer (TPM) x,
channel n and TPM1C2SC is the status and control register for timer 1, channel 2.
10.4.1
TPMxSC contains the overflow status flag and control bits that are used to configure the interrupt enable,
TPM configuration, clock source, and prescale divisor. These controls relate to all channels within this
timer module.
170
CLKS[B:A]
CPWMS
Reset
PS[2:0]
Field
TOIE
TOF
4:3
2:0
7
6
5
W
R
Timer x Status and Control Register (TPMxSC)
TOF
Timer Overflow Flag — This flag is set when the TPM counter changes to 0x0000 after reaching the modulo
value programmed in the TPM counter modulo registers. When the TPM is configured for CPWM, TOF is set
after the counter has reached the value in the modulo register, at the transition to the next lower count value.
Clear TOF by reading the TPM status and control register when TOF is set and then writing a 0 to TOF. If another
TPM overflow occurs before the clearing sequence is complete, the sequence is reset so TOF would remain set
after the clear sequence was completed for the earlier TOF. Reset clears TOF. Writing a 1 to TOF has no effect.
0 TPM counter has not reached modulo value or overflow
1 TPM counter has overflowed
Timer Overflow Interrupt Enable — This read/write bit enables TPM overflow interrupts. If TOIE is set, an
interrupt is generated when TOF equals 1. Reset clears TOIE.
0 TOF interrupts inhibited (use software polling)
1 TOF interrupts enabled
Center-Aligned PWM Select — This read/write bit selects CPWM operating mode. Reset clears this bit so the
TPM operates in up-counting mode for input capture, output compare, and edge-aligned PWM functions. Setting
CPWMS reconfigures the TPM to operate in up-/down-counting mode for CPWM functions. Reset clears
CPWMS.
0 All TPMx channels operate as input capture, output compare, or edge-aligned PWM mode as selected by the
1 All TPMx channels operate in center-aligned PWM mode
Clock Source Select — As shown in
of three clock sources to drive the counter prescaler. The external source and the XCLK are synchronized to the
bus clock by an on-chip synchronization circuit.
Prescale Divisor Select — This 3-bit field selects one of eight divisors for the TPM clock input as shown in
Table
whatever clock source is selected to drive the TPM system.
0
7
MSnB:MSnA control bits in each channel’s status and control register
10-3. This prescaler is located after any clock source synchronization or clock source selection, so it affects
= Unimplemented or Reserved
Figure 10-3. Timer x Status and Control Register (TPMxSC)
TOIE
0
6
Table 10-1. TPMxSC Register Field Descriptions
CPWMS
0
5
MC9S08AW60 Data Sheet, Rev 2
Table
CLKSB
10-2, this 2-bit field is used to disable the TPM system or select one
0
4
Description
CLKSA
3
0
PS2
0
2
Freescale Semiconductor
PS1
0
1
PS0
0
0