STM32L151X8 datasheet(30/133 Pages) STMICROELECTRONICS

30 / 133 page

Functional overview

STM32L151x6/8/B STM32L152x6/8/B

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DocID17659 Rev 12

3.17

CRC (cyclic redundancy check) calculation unit

The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from a 32-bit

data word and a fixed generator polynomial.

Among other applications, CRC-based techniques are used to verify data transmission or

storage integrity. In the scope of the EN/IEC 60335-1 standard, they offer a means of

verifying the Flash memory integrity. The CRC calculation unit helps compute a signature of

the software during runtime, to be compared with a reference signature generated at link-

time and stored at a given memory location.

3.18

Development support

Serial wire JTAG debug port (SWJ-DP)

The ARM SWJ-DP interface is embedded, and is a combined JTAG and serial wire debug

port that enables either a serial wire debug or a JTAG probe to be connected to the target.

The JTAG JTMS and JTCK pins are shared with SWDAT and SWCLK, respectively, and a

specific sequence on the JTMS pin is used to switch between JTAG-DP and SW-DP.

The JTAG port can be permanently disabled with a JTAG fuse.

Embedded Trace Macrocell™

The ARM Embedded Trace Macrocell provides a greater visibility of the instruction and data

flow inside the CPU core by streaming compressed data at a very high rate from the

STM32L151x6/8/B and STM32L152x6/8/B device through a small number of ETM pins to

an external hardware trace port analyzer (TPA) device. The TPA is connected to a host

computer using USB, Ethernet, or any other high-speed channel. Real-time instruction and

data flow activity can be recorded and then formatted for display on the host computer

running debugger software. TPA hardware is commercially available from common

development tool vendors. It operates with third party debugger software tools.

STM32L151x8 Datasheet(PDF) 30 Page - STMicroelectronics