ST L6470H, Руководство пользователя

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L6470 Functional description
Doc ID 16737 Rev 2 27/64
On exit from standby mode the bridges are disabled (HiZ flag high) and whichever motion
command makes the device exiting from High Z state (HardStop and SoftStop included).
Caution: It is not recommended to reset device when outputs are active. The device should be
switched to high impedance state before being reset.
6.13 External switch (SW pin)
The SW pin sources a current towards an external switch in order to test whether it is
CLOSED or OPEN: the SW input is internally pulled-up to V
DD
and detects if the pin is open
or connected to ground (see Figure 11 ).
The SW_F bit of STATUS register indicates if the switch is open (‘0’) or closed (‘1’) (see
paragraph
9.1.22 ); the bit value is refreshed at every system clock cycle (125 ns). SW_EVN
flag of STATUS register is raised when a switch turn-on event (SW input falling edge) is
detected (see paragraph
9.1.22 ). A GetStatus command releases the SW_EVN flag (see
paragraph 9.2.20 .
By default a switch turn-on event causes a HardStop interrupt (SW_MODE bit of CONFIG
register set to ‘0’). Otherwise (SW_MODE bit of CONFIG register set to ‘1’), switch input
events do not cause interrupts and the switch status information are at user disposal (see
Table 33 , paragraph 9.1.22 ).
The switch input can used by GoUntil and ReleaseSW commands as described in
paragraph
9.2.10 and 7.3 .
If the SW input is not used, it should be connected to VDD.
Figure 11. External switch connection
!-V
%XTERNAL
3WITCH
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