mc68hc708mp16 Freescale Semiconductor, Inc, mc68hc708mp16 Datasheet - Page 235

• Manufacturer Part Number: mc68hc708mp16
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

12.4.4.3 PWM Initialization
MC68HC708MP16
Freescale Semiconductor
NOTE:
—
Rev. 3.1
status and control register (TBSC1) is unused. While the MS0B bit is set,
the channel 1 pin, PTE5/TCH1B, is available as a general-purpose I/O
pin.
Channels 2 and 3 can be linked to form a buffered PWM channel whose
output appears on the PTE6/TCH2B pin. The TIMB channel registers of
the linked pair alternately control the pulse width of the output.
Setting the MS2B bit in TIMB channel 2 status and control register
(TBSC2) links channel 2 and channel 3. The TIMB channel 2 registers
initially control the pulse width on the PTE6/TCH2B pin. Writing to the
TIMB channel 3 registers enables the TIMB channel 3 registers to
synchronously control the pulse width at the beginning of the next PWM
period. At each subsequent overflow, the TIMB channel registers (2 or
3) that control the pulse width are the ones written to last. TBSC2
controls and monitors the buffered PWM function, and TIMB channel 3
status and control register (TBSC3) is unused. While the MS2B bit is set,
the channel 3 pin, PTE7/TCH3B, is available as a general-purpose I/O
pin.
In buffered PWM signal generation, do not write new pulse width values
to the currently active channel registers. Writing to the active channel
registers is the same as generating unbuffered PWM signals.
To ensure correct operation when generating unbuffered or buffered
PWM signals, use the following initialization procedure:
1. In the TIMB status and control register (TBSC):
2. In the TIMB counter modulo registers (TBMODH:TBMODL), write
3. In the TIMB channel x registers (TBCHxH:TBCHxL), write the
a. Stop the TIMB counter by setting the TIMB stop bit, TSTOP.
b. Reset the TIMB counter by setting the TIMB reset bit, TRST.
the value for the required PWM period.
value for the required pulse width.
Timer Interface Module B (TIMB)
Timer Interface Module B (TIMB)
Technical Data
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