STMicroelectronics FlexSPIN: SPI configurable stepper and DC multi motor driver evaluation board EVAL6460 EVAL6460 Fiche De Données
Codes de produits
EVAL6460
General purpose PWM
L6460
90/139
Doc ID 17713 Rev 1
19
General purpose PWM
L6460 includes three general purpose PWM generators that can be redirected on GPIO
pins (see
pins (see
). Two of these generators (Aux_PWM_1 and Aux_PWM_2) work with
a fixed period F
OSC
/512 and have a programmable duty cycle; the other one (GP_PWM)
has a programmable base time clock and a programmable time for both high and low levels.
19.1
General purpose PWM generators 1 and 2 (AuxPwm1 and
AuxPwm2)
AuxPwm2)
The Duty cycle of these PWM generators can be changed by writing the AuxPwmXCtrl bits
(where X can be 1 or 2) in the AuxPwm1Ctrl and AuxPwm2Ctrl registers. Their positive duty
cycle will change according to the equation:
(where X can be 1 or 2) in the AuxPwm1Ctrl and AuxPwm2Ctrl registers. Their positive duty
cycle will change according to the equation:
According to this equation a programmed “0” value will cause a 0% duty cycle (output
always at logic level 0).
always at logic level 0).
19.2
Programmable PWM generator (GpPwm)
GpPWM has a programmable base clock that can be changed by programming the
GpPwmBase[6:0] bits in the GpPwmBase register. The clock will change according to the
equation:
GpPwmBase[6:0] bits in the GpPwmBase register. The clock will change according to the
equation:
The high and low level duration (expressed in base clock periods), can be programmed
writing the GpPwmHigh[7:0] and GpPwmLow[7:0] bits in the GpPwmCtrl register so they will
change according to following equations:
writing the GpPwmHigh[7:0] and GpPwmLow[7:0] bits in the GpPwmCtrl register so they will
change according to following equations:
The resulting period of the PWM will be:
and the positive duty cycle will result:
A programmed value of 0 in GpPwmHigh[7:0] and GpPwmLow[7:0] bits will force the PWM
generator output to be always at logic level “0”.
generator output to be always at logic level “0”.
PWM_X_DUTY
AuxPwmXCtrl 9:0
[
]/512
=
PWM_BASE_PERIOD
GpPwmBase 6:0
[
] 1
+
(
) Tosc
×
=
High_level_Time
GpPwmHigh 7:0
[
] PWM_BASE_PERIOD
×
=
Low_level_Time
GpPwmLow 7:0
[
] PWM_BASE_PERIOD
×
=
Period
GpPwmHigh 7:0
[
] GpPwmLow 7:0
[
]
+
(
) PWM_BASE_PERIOD
+
=
DutyCycle
High_level_Time
High_level_Time
Low_level_Time
+
-----------------------------------------------------------------------------------------------
GpPwmHigh 7:0
[
]
GpPwmHigh 7:0
[
] GpPwmLow 7:0
[
]
+
---------------------------------------------------------------------------------------------------------
=
=