ST7MC2S4 STMicroelectronics, ST7MC2S4 Datasheet - Page 165

• Manufacturer Part Number: ST7MC2S4
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC,BRUSHLESS MOTOR CONTROL, 5 TIMERS, SPI, LINSCI(TM)
• Manufacturer: STMicroelectronics

MOTOR CONTROLLER (Cont’d)
10.6.6.13 Encoder Mode (IS[1:0] = 11)
Figure 90
ard digital incremental encoder and associated in-
formation:
Figure 89. Tacho Capture events configured by the TES[1:0] bits
Figure 90. Incremental Encoder output signals and derived information
– Two 90° phased square signals with variable
– Clock derived from incoming signal edges,
– Direction information determined by the rela-
frequency proportional to the speed; they
must be connected to MCIA and MCIB input
pins,
tive phase shift of input signals ( + or -90°).
Capture
Encoder
Tacho
inputs
(EDIR bit)
Direction
shows the signals delivered by a stand-
Encoder
Clock
Tacho
input
MCIA
MCIB
The Incremental Encoder Interface block aims at
extracting these signals. As input logic is both ris-
ing and falling edge sensitive (independently from
TES[1:0] bits setting), resulting clock frequency is
four times the one of the input signals, thus in-
creasing resolution for measurements.
It may be noticed that Direction bit (EDIR bit in
MCRC register) is read only and that it does’nt af-
fect counting direction of clocked timer (cf
). As a result, one cannot extract position informa-
tion from encoder inputs during speed reversal.
Sampling of MCIA to determine direction
ST7MC1xx/ST7MC2xx
TES[1:0]=11
TES[1:0]=01
TES[1:0]=10
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