Peripheral migration

TN1176

10/15

DocID026267 Rev 1

Note:

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.

3.1.3

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.

3.1.4

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.

For more details about LCD rail decoupling please refer to the STM32L100xx,

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, and to the STM32L15xx6/8/B and STM32L100x6/8/B datasheets.

3.1.5

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.

3.1.6

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.