MCBSTM32EXL Keil, MCBSTM32EXL Datasheet - Page 50

• Manufacturer Part Number: MCBSTM32EXL
• Description: BOARD EVALUATION FOR STM32F103ZE
• Manufacturer: Keil

Specifications of MCBSTM32EXL

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

CRC calculation unit
3
3.1
3.2
50/995
CRC calculation unit
Low-density devices are STM32F101xx, STM32F102xx and STM32F103xx
microcontrollers where the Flash memory density ranges between 16 and 32 Kbytes.
Medium-density devices are STM32F101xx, STM32F102xx and STM32F103xx
microcontrollers where the Flash memory density ranges between 64 and 128 Kbytes.
High-density devices are STM32F101xx and STM32F103xx microcontrollers where the
Flash memory density ranges between 256 and 512 Kbytes.
Connectivity line devices are STM32F105xx and STM32F107xx microcontrollers.
This section applies to the whole STM32F10xxx family, unless otherwise specified.
CRC introduction
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.
CRC main features
●
●
●
●
The block diagram is shown in
Figure 3.
Uses CRC-32 (Ethernet) polynomial: 0x4C11DB7
–
Single input/output 32-bit data register
CRC computation done in 4 AHB clock cycles (HCLK)
General-purpose 8-bit register (can be used for temporary storage)
X
32
CRC calculation unit block diagram
+ X
26
32-bit (write access)
+ X
23
+ X
22
CRC computation (polynomial: 0x4C11DB7)
Doc ID 13902 Rev 9
Figure
+ X
16
3.
+ X
Data register (input)
Data register (output)
12
AHB bus
+ X
11
+ X
10
32-bit (read access)
+X
8
+ X
7
+ X
5
+ X
4
+ X
ai14968
2
+ X +1
RM0008