TN1176 Datasheet, PDF (10/15 Pages) STMicroelectronics – To ease the development of STM32 microcontroller applications

Peripheral migration
TN1176
Note:
3.1.3
3.1.4
3.1.5
3.1.6
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which STM32L15xx6/8/B is ‘Cat.1’ device, STM32L15xx6/8/B-A is ‘Cat.2’ device,
STM32L100x6/8/B is ‘Cat.1’ device, STM32L100x6/8/B-A is ‘Cat.2’ device.
CSS on LSE
The Clock Security System (CSS) has been extended to LSE clock in the
STM32L15xx6/8/B-A and STM32L100x6/8/B-A devices, while in STM32L15xx6/8/B and
STM32L100x6/8/B, the CSS was only for HSE clock.
The enhanced CSS is backward compatible. To use the new CSS feature, it is necessary to
use the updated version of STM32L1xx Standard Peripherals Library.
LCD rail decoupling
The external decoupling capability of LCD rails was implemented to improve the LCD
contrast (for example for large LCD displays with higher segments capacity). On
STM32L15xx6/8/B-A or STM32L100x6/8/B-A, specific pins can be connected to external
capacitors that maintain a stable LCD rail voltage while driving the LCD segments.
The backward compatibility is fulfilled, there is not need of any software change. To use the
new feature, the dedicated pins must be configured as input, the external capacitors should
be connected and the LCD_CAPA[4:0] bits in the SYSCFG_PMC register must be
configured.
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RM0038 in which STM32L15xx6/8/B is ‘Cat.1’ device, STM32L15xx6/8/B-A is ‘Cat.2’
device, and to the STM32L15xx6/8/B and STM32L100x6/8/B datasheets.
Proprietary code protection (PCROP)
The read protection of a given Flash area is implement in STM32L15xx6/8/B-A device, but
not in STM32L100x6/8/B-A device. The Flash area cannot be read by any access (including
software), it can be only executed. It can be used as intellectual property read protection of
proprietary third party code which can be executed on customer side.
The implementation of this proprietary code read out protection (PCROP) is backward
compatible. To use the PCROP feature it is necessary to correctly program the added option
bytes (SPRMOD and WRPx option bytes).
For additional information, please refer to the STM32L100xx, STM32L151xx, STM32L152xx
and STM32L162xx advanced ARM®-based 32-bit MCUs reference manual RM0038 in
which STM32L15xx6/8/B is ‘Cat.1’ device, STM32L15xx6/8/B-A is ‘Cat.2’ device,
STM32L100x6/8/B is ‘Cat.1’ device, STM32L100x6/8/B-A is ‘Cat.2’ device.
Number of backup registers
The number of backup registers has been decreased in STM32L15xx6/8/B-A device. The
number of backup registers in the respective devices is as follows:
 STM32L15xx6/8/B: 80 backup registers,
 STM32L15xx6/8/B-A: 20 backup registers
 STM32L100x6/8/B-A and STM32L100x6/8/B: 20 backup registers.
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