ST7FMC1K2B3 STMICROELECTRONICS [STMicroelectronics], ST7FMC1K2B3 Datasheet - Page 164

• Manufacturer Part Number: ST7FMC1K2B3
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST7MC1xx/ST7MC2xx
MOTOR CONTROLLER (Cont’d)
10.6.6.11 Speed Sensor Mode
This mode is entered whenever the Tacho Edge
Selection bits in the MPAR register are not both re-
set (TES[1:0] = 01, 10 or 11). The corresponding
block diagram is shown in
Either Incremental Encoder or Tachogenerator-
type speed sensor can be selected with the IS[1:0]
bits in the MPHST register.
10.6.6.12 Tachogenerator Mode (IS[1:0] = 00, 01
or 10)
Any of the MCIx input pins can be used as a tacho-
generator input, with a digital signal (externally
amplified for instance); the two remaining pins can
be used as standard I/O ports.
A digital multiplexer connects the chosen MCIx in-
put to an edge detection block. Input selection is
done with the IS[1:0] bits in the MPHST register.
An edge selection block is used to select one of
three ways to trigger capture events: rising edge,
falling edge or both rising and falling edge sensi-
Figure 88. Input Stage in Speed Sensor Mode (TES[1:0] bits = 01, 10, 11)
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1
Tacho
Tacho
Tacho
Encoder
Encoder
Free I/O
§
§
§
or
or
or
MCIA
MCIB
MCIC
Input Block
Figure
88.
00
01
10
Input
Input Comparator Block
n
Sel
MPHST Register
IS[1:0]
tive; set-up is done with the TES[1:0] bits (keeping
in mind that TES[1:0] = 00 configuration is re-
served for Position Sensor / Sensorless Modes).
Having only one edge selected eliminates any in-
coming signal dissymmetry, which may due to
pole-to-pole magnet dissymmetry or from a com-
parator threshold with low level signals.
Figure 89
ly with different tacho input and TES bit settings.
Note on Hall Sensors: This configuration is also
suitable for motors using 3 hall sensors for position
detection and not driven in six-step mode (refer to
“Speed Measurement Mode” on page
Note on initializing the Input Stage: As the
IS[1:0] bits in the MPHST register are preload bits
(new values taken into account at C event), the in-
itialization value of the IS[1:0] bits has to be en-
tered in Direct Access mode. This is done by set-
ting the DAC bit in the MCRA register during the
speed sensor input initialization routine.
MPAR Register
or
TES[1:0]
presents the signals generated internal-
or
In2
In1
Incremental
§
interface
Encoder
= According to IS[1:0] bits setting
Event Detection
Capture
Tacho
Clk
D
MCRC Register
Direction
EDIR bit
Encoder
Clock
180).