DocID17496 Rev 7

27/33

AN3216

Reference design

32

7

Reference design

7.1

Description

The reference design shown in Figure 16, is based on the STM32L152VB(T6)

.

This reference design can be tailored to any STM32L1xxx device with a different package,

using the pin correspondence given in Table 7: Reference connection for all packages.

7.1.1

Clock

Two clock sources are used for the microcontroller:

•

LSE: X1– 32.768 kHz crystal for the embedded RTC

•

HSE: X2– 8 MHz crystal for the STM32L1xxx microcontroller

Refer to Section 3: Clocks on page 16.

7.1.2

Reset

The reset signal in Figure 16 is active low. The reset sources include:

•

Reset button (B1)

•

Debugging tools via the connector CN1

Refer to Section 2.3: Reset and power supply supervisor on page 11.

7.1.3

Boot mode

The boot option is configured by setting switches SW2 (Boot 0) and SW1 (Boot 1). Refer to

Section 4: Boot configuration on page 20.

Note:

When waking up from Standby mode, the Boot pins are sampled. In this situation, you need

to pay attention to their values.

7.1.4

SWJ interface

The reference design shows the connection between the STM32L1xxx and a standard

JTAG connector. Refer to Section 5: Debug management on page 22.

Note:

It is recommended to connect the reset pins so as to be able to reset the application from

the tools.

7.1.5

Power supply

Refer to Section 2: Power supplies on page 7.