DocID022881 Rev 10
27/123
STM32L162VC, STM32L162RC
46
implementation based on a surface charge transfer acquisition principle. It consists of
charging the sensor capacitance and then transferring a part of the accumulated charges
into a sampling capacitor until the voltage across this capacitor has reached a specific
threshold. The capacitive sensing acquisition only requires few external components to
operate. This acquisition is managed directly by the GPIOs, timers and analog I/O groups
(see
Section 3.14: System configuration controller and routing interface
Reliable touch sensing functionality can be quickly and easily implemented using the free
STM32L1xx STMTouch touch sensing firmware library.
3.16 AES
The AES Hardware Accelerator can be used to encrypt and decrypt data using the AES
algorithm (compatible with FIPS PUB 197, 2001 Nov 26).
•
Key scheduler
•
Key derivation for decryption
•
128-bit data block processed
•
128-bit key length
•
213 clock cycles to encrypt/decrypt one 128-bit block
•
Electronic codebook (ECB), cypher block chaining (CBC), and counter mode (CTR)
supported by hardware.
AES data flow can be served by 2ch (D
IN
/D
OUT
) of the DMA2 controller
3.17
Timers and watchdogs
The ultra-low-power STM32L162xC devices include seven general-purpose timers, two
basic timers, and two watchdog timers.
compares the features of the general-purpose and basic timers.
Table 7. Timer feature comparison
Timer
Counter
resolution
Counter type
Prescaler factor
DMA
request
generation
Capture/compare
channels
Complementary
outputs
TIM2,
TIM3,
TIM4
16-bit
Up, down,
up/down
Any integer between
1 and 65536
Yes
4
No
TIM5
32-bit
Up, down,
up/down
Any integer between
1 and 65536
Yes
4
No
TIM9
16-bit
Up, down,
up/down
Any integer between
1 and 65536
No
2
No
TIM10,
TIM11
16-bit
Up
Any integer between
1 and 65536
No
1
No
TIM6,
TIM7
16-bit
Up
Any integer between
1 and 65536
Yes
0
No