Migrating applications from ST7FLITE1x to ST7FLITE1xB

3 New features in ST7FLITE1xB

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3.2.3

Dead time generation

A programmable dead time can be inserted between PWM0 and PWM1. This is required for

half-bridge driving where PWM signals must not be overlapped.

3.2.4

Long input capture

In addition to the normal Input Capture mode, Long Input Capture is available in ST7FLITE1xB.

Using this mode, pulses that last more than 8us can be measured with an accuracy of 4us. This

configuration allows you to cascade the Lite Timer and the 12-bit AT3 Timer to get a 20-bit Input

Capture value.

3.2.5

One pulse mode

One pulse mode can be used to control PWM2/3 signal with External LTIC pin. This mode is

only available in dual timer mode.

3.2.6

Forced update

In order not to wait for CNTRx overflow to load the value into the active DCRx registers, a

programmable CNTRx overflow is provided. For both counters, a separate bit is provided which

when set makes the counters start with the overflow value i.e. FFFh. After overflow, the

counters start counting from their respective auto reload registers.

3.3

Analog comparator

ST7FLITE1B has an analog comparator and an internal voltage reference. The voltage

reference can be external or internal, selectable under program control. The comparator input

pins, COMPIN+ and COMPIN- are also connected to A/D Converter.

3.3.1

On-chip analog comparator

The analog comparator compares the voltage at the two inputs COMPIN+ and COMPIN- which

are connected to VP and VN at the input of the comparator. When the analog input at

COMPIN+ is less than analog input at COMPIN-, the output of the comparator is 0. When the

analog input at COMPIN+ is greater than analog input at COMPIN- the output of the

comparator is 1.

3.3.2

Programmable internal voltage reference

The voltage reference module can be configured to connect the comparator pin to one of the

following sources:

●

Fixed internal voltage bandgap: The voltage reference module can generate a fixed

voltage reference of 1.2V on the VN input.

●

Programmable internal reference voltage: The internal voltage reference module can

provide 16 distinct internally generated voltage levels from 0.2V to 3.2V each at a step

0.2V on the comparator pin VN.

●

External voltage reference: If you want to have a reference voltage other than the one

generated by the internal voltage reference module, you can connect the COMPIN- to an

external voltage source.