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
Tabl e 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
37
6
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