Data Sheet

4.17 LED PWM 4 PERIPHERAL INTERFACE
4.17 LED PWM
The LED PWM controller can generate 16 independent channels of digital waveforms with the configurable periods
and configurable duties.
The 16 channels of digital waveforms operate at 80 MHz APB clock, among which 8 channels have the option of
using the 8 MHz oscillator clock. Each channel can select a 20-bit timer with configurable counting range and its
accuracy of duty can be up to 16 bits with the 1 ms period.
The software can change the duty immediately. Moreover, each channel supports step-by-step duty increasing or
decreasing automatically. It is useful for the LED RGB color gradient generator.
4.18 Serial Peripheral Interface (SPI)
ESP32 features three SPIs (SPI, HSPI and VSPI) in slave and master modes in 1-line full-duplex and 1/2/4-line
half-duplex communication modes. These SPIs also support the following general-purpose SPI features:
• 4 timing modes of the SPI format transfer that depend on the polarity (POL) and the phase (PHA)
• up to 80 MHz and the divided clocks of 80 MHz
• up to 64-Byte FIFO
All SPIs can also be used to connect to the external Flash/SRAM and LCD. Each SPI can be served by DMA
controllers.
4.19 Accelerator
ESP32 is equipped with hardware accelerators of general algorithms, such as AES (FIPS PUB 197), SHA (FIPS
PUB 180-4), RSA, and ECC, which support independent arithmetic such as Big Integer Multiplication and Big
Integer Modular Multiplication. The maximum operation length for RSA, ECC, Big Integer Multiply and Big Integer
Modular Multiplication is 4096 bits.
The hardware accelerators greatly improve operation speed and reduce software complexity. They also support
code encryption and dynamic decryption�which ensures that codes in the Flash will not be stolen.
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