st52t430 STMicroelectronics, st52t430 Datasheet - Page 52

• Manufacturer Part Number: st52t430
• Description: 8-bit Intelligent Controller Unit Icu Three Timer/pwms, Adc, Sci
• Manufacturer: STMicroelectronics

Figure 10.4 PWM Mode with Auto Reload
EDGE(Period Counter): After reset, on the first
T0STRT rising edge, TIMER 0 starts counting and
at the next rising edge it stops. In this manner, the
period of an external signal may be measured.
Timer x output signal, TIMERxOUT is a signal with
a frequency equal to the 16 bit-Prescaler x output
signal, TMRCLKx, divided by the Output Register
PWM_x_COUNT value (8 bit) (Output Registers 3,
5 or 7. See Table 2.4), which is the value to count.
There can be two types of TIMERxOUT waveform:
type 1: TIMERxOUT waveform equal to a square
wave with a 50% duty-cycle.
type 2: TIMERxOUT waveform equal to a pulse
signal with the pulse duration equal to the
Prescaler x output signal.
For each Timer x, the TIMERxOUT waveform type
can be selected by setting the correspondent
TMRWx bit of REG_CONF6, REG_CONF9 and
REG_CONF11 registers (see Table 10.2, Table
10.5 and Table 10.7)
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compare
value
reload
register
Output
PWM
255
0
Ton
T
10.2 PWM Mode
For each timer, PWM working mode is obtained by
setting the correspondent TxMODE bits of
REG_CONF5, REG_CONF8 and REG_CONF10
registers to 1 (see Table 10.1, Table 10.4 and
Table 10.6).
TIMERxOUT, in PWM Mode consists of a signal
with a fixed period, whose duty cycle can be
modified by the user.
The TIMERxOUT signal can be available on the
TxOUT pin and the TIMERxOUT inverted signal
can be available on the TxOUT pin by setting the
PxSL bits of REG_CONF12 and REG_CONF16
(see Table 10.8 and Table 10.9)
The PWM TIMERxOUT period can be determined
by setting the 16-bit prescaler x output and an
initial autoreload 8-bit counter value stored in the
Output Register PWM_x_RELOAD, as illustrated
in Figure 10.4.
NOTE: the Start/Stop and Set/Reset signals
should be moved together in PWM mode. If the
Start/Stop bit is reset during the PWM mode
working, the TxOUT signal keeps its status
until the next start.
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