Datasheet

TMC8462 Datasheet • Document Revision V1.5 • 2019-June-21

185 / 204

7.20 MFC IO Emergency Switch Input

The MFC IO block oﬀers a dedicated emergency switch input called MFC_NES. It is low active.

It is used to set speciﬁc MFCIOxx outputs to a a conﬁgurable safe state in case of emergency.

The MFC_NES pin has weak internal pull-down resistor. A microcontroller or another circuit must actively

drive a high level at MFC_NES for normal operation.

The emergency switch input MFC_NES is only active if it is masked in the MFCIO_IRQ_CFG register at bit 23.

Otherwise it is ignored.

If MFC_NES triggers (low level), the respective outputs take their conﬁgured safe values. The internal

emergency switch ﬂag remains set in register MFCIO_IRQ_FLAGS even when the external pin MFC_NES is

already driven high again.

MFC_NES has impact on the following functional units and outputs:

•

MFC IO PWM block: the PWM high and low side gate outputs are set to a deﬁned conﬁgurable safe

oﬀ-state.

•

MFC IO GPIO block: all GPIOs that are conﬁgured as output ports via the crossbar are set to a deﬁned

conﬁgurable safe oﬀ-state.

• MFC IO Step and Direction block: the step outputs and internal step counters freeze.

• The MFCIO_IRQ signal will be triggered.

Note

The emergency ﬂag can only be unset be either doing a reset or by actively

writing 2 times into the MFCIO_IRQ_CFG register at bit position 23. Thereby, the

existing IRQ mask at bit 23 must ﬁrst be set to zero and then set back to 1 again.

This way, the internal emergency ﬂag is unset. This can be done either by the

local application controller or by the EtherCAT master if it has access to register

MFCIO_IRQ_CFG.

Terms of delivery and rights to technical change reserved.

Download newest version at www.trinamic.com