ST7MC1xx/ST7MC2xx
MOTOR CONTROLLER (Cont’d)
10.6.10 PWM Generator Block
The PWM generator block produces three inde-
pendent PWM signals based on a single carrier
frequency with individually adjustable duty cycles.
Depending on the motor driving method, one or
three of these signals may be redirected to the oth-
er functional blocks of the motor control peripheral,
using the PCN bit in the MDTG register.
When driving PM BLDC motors in six-step mode
(voltage mode only, either sensored or sensor-
less) a single PWM signal (Phase U) is used to
supply the Input Stage, PWM and Channel Man-
ager blocks according to the selected modes.
For other kind of motors requiring independent
PWM control for each of the three phases, all
PWM signals (Phases U, V and W) are directed to
the channel manager, in which deadtime or a high
Figure 117. PWM generator block diagram
frequency carrier may be added. This is the case
of AC induction motors or PMAC motors for in-
stance, supplied with 120° shifted sinewaves in
voltage mode.
10.6.10.1 Main Features
■ 12-bit PWM free-running Up/Down Counter with
up to 16MHz input clock (Fmtc).
■ Edge-aligned and center-aligned PWM
operating modes
■ Possibility to re-load compare registers twice
per PWM period in center-aligned mode
■ Full-scale PWM generation
■ PWM update interrupt generation
■ 8-bit repetition counter
■ 8-bit PWM mode
■ Timer re-synchronisation feature
U
12-bit Compare 0 Register
MREP Register
MPCR Register
Fmtc
Prescaler
Up to 16MHz PCP[2:0] bits
Repetition
counter
U
Clear or Up/Down
MPCR Register
12-bit PWM Counter
CMS bit
U
13-bit Compare U Register
U
13-bit Compare V Register
U
13-bit Compare W Register
Notes:
Reg Preload registers transferred
to active registers on U event
event:
U Update of compare registers
PWM interrupt generation
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