3 New features in ST7FLITE1xB

Migrating applications from ST7FLITE1x to ST7FLITE1xB

8/13

3

New features in ST7FLITE1xB

3.1

Clock management

Some changes have been made in the clock management. They are as follows:

1.

It is possible to also run at 4MHz with RC and PLL from 2.7V to 5.5V. An additional

PLLTST register is available in ST7FLITE1xB containing the PLLDIV2 bit which allows you

to divide the PLL output clock by 2. Hence, x4 PLL (x4PLL from 2.7V to 3.3V and x8PLL /

2 from 3.3V to 5.5V) is effectively available for the entire operating voltage range of the

device (2.7V to 5.5V).

2.

Ceramic Oscillator has a self-controlled gain feature, an oscillator of any frequency from 1

to 16 MHz can be connected to the OSC1 and OSC2 pins. For the ST7FLITE1xB through

the option bytes External Oscillator is enabled but the frequency range need not be

selected. For STFLITE1x the frequency range of the oscillator should also be selected.

Refer to section 7 for details.

3.

The Internal RC of ST7LITE1x has to be calibrated by writing a 8-bit calibration value in

the RCCR (RC Control Register). In contrast, the Internal RC of ST7LITE1xB must be

calibrated by writing a 10-bit calibration value in the RCCR (RC Control Register) and in

bits 6:5 in the SICSR (SI Control Status Register).

4.

The predefined calibration values for ST7LITE1x: RCCR0 @ 5V and RCCR1 @ 3V are

stored at locations FFDEh and FFDFh for ST7LITE1x.

The predefined calibration values for ST7LITE1xB: RCCRH0 & RCCRL0 @ 5V and

RCCRH1 & RCCRL1 @ 3.3V are stored at locations DEE0h, DEE1h, DEE2h and DEE3h.

5.

The predefined calibration value for ST7LITE1x: RCCR1 @ 3V is used for obtaining an

Internal RC frequency of 700KHz. The value for ST7LITE1xB, RCCRH1 & RCCRL1 @

3.3V is used for obtaining an internal RC frequency of 1MHz.

3.2

12-bit autoreload timer

The 12-bit Auto-Reload Timer has been modified to provide more features like Dual counters,

Long Input Capture, Internal Break Control, Dead Time generation, One Pulse mode and

Forced Update. All the other features of the timer do not change.

3.2.1

Dual counters

Apart from Single Timer mode, Dual Timer mode is available with two 12-bit upcounters and

two 12-bit autoreload registers.

3.2.2

Break function

Some additions in this feature are

●

Break function can be activated through an Internal Comparator output

●

Break active level can be programmed instead of just low level in ST7FLITE1x

●

When the break function is active, the break pattern is forced on the PWMx outputs if OEx

is set whereas in ST7FLITE1x the active break pattern is forced on the PWMx outputs

irrespective of whether OEx bit is set or reset.