Preset in down counting mode (TSX CTY 2A/4A)

At a Glance

Presetting initializes the down counting register to a value preset by the software. Preset is:

triggered
- by the hardware: on the rising or falling edge of the IPres ST_IPRES (%IWr.m.c.2.3) physical input with pre-enabled software, Preset enable command,
- directly by the software: Direct preset command.
automatic, will be done when the zero value is crossed.

NOTE: the two types of preset (triggered and automatic) are independent and can co-exist.

Illustration

The figure below represents the preset function triggered by the hardware. The associated language objects are described in the default objects section.

Time diagrams

The following time diagrams show the different cases for preset with or without automatic reloading when crossing the zero value threshold.

The time diagram below shows a preset triggered by IPres, then a direct (software) preset. Zero value is crossed without automatic preset.

The time diagram below shows a preset triggered by IPres, a direct preset, and an automatic preset when crossing the zero value.