Technical Reference Manual - Espressif

1 ESP32 Technical Reference ManualVersion SystemsCopyright This ManualTheESP32 Technical Reference Manualis addressed to application developers. The Manual provides detailedand complete information on how to use the ESP32 memory and pin definition, electrical characteristics, and package information, please seeESP32 UpdatesPlease always refer to the latest version HistoryFor any changes to this document over time, please refer to thelast Change NotificationEspressif provides email notifications to keep customers updated on changes to Technical documentation.

2 Pleasesubscribe certificates for Espressif products System and Functional Address Embedded Internal ROM Internal ROM Internal SRAM Internal SRAM Internal SRAM RTC FAST RTC SLOW External Asymmetric PID controller Non-Contiguous Peripheral Memory Memory Speed332 Interrupt Matrix (INTERRUPT) Functional Peripheral Interrupt CPU Allocate Peripheral Interrupt Sources to Peripheral Interrupt on CPU NMI Interrupt Query Current Interrupt Status of Peripheral Interrupt Registers383 Reset and System Reset System Clock CPU Peripheral APB_CLK Source42 Espressif Systems3 Submit Documentation FeedbackESP32 TRM (Version ) REF_TICK LEDC_SCLK APLL_SCLK PLL_D2_CLK Clock Source Wi-Fi BT RTC Audio PLL444 IO_MUX and GPIO Matrix (GPIO, IO_MUX)

3 Peripheral Input via GPIO Functional Simple GPIO Peripheral Output via GPIO Functional Simple GPIO Direct I/O via Functional RTC IO_MUX for Low Power and Analog Functional Light-sleep Mode Pin Pad Hold I/O Pad Power VDD_SDIO Power Peripheral Signal IO_MUX Pad RTC_MUX Pin Register GPIO Matrix Register IO MUX Register RTC IO MUX Register GPIO Matrix IO MUX RTC IO MUX Registers735 DPort Functional System and Memory Register87 Espressif Systems4 Submit Documentation FeedbackESP32 TRM (Version ) Reset and Clock Interrupt Matrix DMA MPU/MMU APP_CPU controller Peripheral Clock Gating and Register Registers966 DMA controller (DMA) Functional DMA Engine Linked UART DMA (UDMA) SPI DMA I2S DMA Interface1167 SPI controller (SPI) SPI GP-SPI Four-line Full-duplex GP-SPI Four-line Half-duplex GP-SPI Three-line Half-duplex GP-SPI Data GP-SPI Clock GP-SPI Clock Polarity (CPOL) and Clock Phase (CPHA)

4 GP-SPI Parallel Communication Format of Parallel GP-SPI Interrupt SPI DMA Register Registers1288 SDIO Slave Functional SDIO Slave Block Sending and Receiving Data on SDIO Register DMA152 Espressif Systems5 Submit Documentation FeedbackESP32 TRM (Version ) Packet-Sending/-Receiving Sending Packets to SDIO Receiving Packets from SDIO SDIO Bus Host Slave Register SLC SLC Host HINF Registers1829 SD/MMC Host SD/MMC External Interface Functional SD/MMC Host controller Command Data Data Transmit Data Receive Software Restrictions for Proper CIU RAM for Receiving and Sending Transmit RAM Receive RAM Descriptor The Structure of a Linked DMAC DMAC Transmission DMAC Reception Clock Phase

5 Register Registers19510 ethernet media access controller (MAC) Transmit Transmit Flow Retransmission During a Receive Operation216 Espressif Systems6 Submit Documentation FeedbackESP32 TRM (Version ) Reception Receive Frame Receive Flow Reception of Multiple Error Receive Status MAC Interrupt MAC Address Unicast Destination Address Multicast Destination Address Broadcast Address Unicast Source Address Inverse Filtering Good Transmitted Frames and Received EMAC_MTL (MAC Transaction Layer) PHY MII ( media Independent Interface) Interface Signals Between MII and MII RMII (Reduced media -Independent Interface) RMII Interface Signal RMII Station Management Agent (SMA) RMII ethernet DMA Linked List Transmit Receive Register Registers24011 I2C controller (I2C) Functional I2C Bus I2C cmd I2C Master Writes to Master Reads from Register Registers29112 I2S controller (I2S)302 Espressif Systems7 Submit Documentation FeedbackESP32 TRM (Version )

6 The Clock of I2S I2S Supported Audio Philips MSB Alignment PCM Module FIFO Sending Receiving I2S Master/Slave I2S Camera-LCD LCD Master Transmitting Camera Slave Receiving ADC/DAC I2S FIFO DMA Register Registers31813 UART controller (UART) UART Functional UART UART Baud Rate UART Data Flow Hardware Flow Software Flow UART UART UHCI Register UART UHCI Registers34614 LED PWM controller (LEDC) Introduction378 Espressif Systems8 Submit Documentation FeedbackESP32 TRM (Version ) Functional Register Registers38415 Remote Control Peripheral (RMT) Functional RMT RMT Register Registers39716 Motor Control PWM (PWM)

7 Prescaler Timer Operator Fault Detection Capture PWM Timer Configurations of the PWM Timer PWM Timer s Working Modes and Timing Event PWM Timer Shadow PWM Timer Synchronization and Phase PWM Operator PWM Generator Dead Time Generator PWM Carrier Fault Handler Capture Capture Capture Register Registers438 Espressif Systems9 Submit Documentation FeedbackESP32 TRM (Version )Contents17 Pulse Count controller (PCNT) Functional Counter Channel Register Registers48918 Timer Group (TIMG) Functional 16-bit 64-bit Time-base Alarm Register Registers49719 Watchdog Timers (WDT)

8 Functional Operating Write Flash Boot Registers50620 eFuse Functional System Parameter System Parameter System Parameter Programming of System Software Reading of System The Use of System Parameters by Hardware Register Summary515 Espressif Systems10 Submit Documentation FeedbackESP32 TRM (Version ) Registers51821 Two wire Automotive Interface (TWAI) Functional TWAI TWAI Data Frames and Remote Error and Overload Interframe TWAI Error Error Error TWAI Bit Nominal Hard Synchronization and Architectural Registers Bit Stream Error Management Bit Timing Acceptance Receive Functional Reset Operation Bit Interrupt Receive Interrupt (RXI) Transmit Interrupt (TXI) Error Warning Interrupt (EWI) Data Overrun Interrupt (DOI) Error Passive Interrupt (TXI) Arbitration Lost Interrupt (ALI) Bus Error Interrupt (BEI)

9 Transmit and Receive Overview of Frame Frame Frame Receive FIFO and Data Acceptance Single Filter Mode547 Espressif Systems11 Submit Documentation FeedbackESP32 TRM (Version ) Dual FIlter Error Error Warning Error Bus-Off and Bus-Off Error Code Arbitration Lost Register Registers55422 AES Accelerator (AES) Functional AES Algorithm Key, Plaintext and Encryption and Decryption Register Registers57123 SHA Accelerator (SHA) Functional Padding and Parsing the Message Hash Register Registers57624 RSA Accelerator (RSA) Functional Large Number Modular Large Number Modular Large Number Register Registers58625 Random Number Generator (RNG) Introduction588 Espressif Systems12 Submit Documentation FeedbackESP32 TRM (Version ) Functional Programming Register Register58926 External Memory Encryption and Decryption (FLASH)

10 Functional Key Flash Encryption Flash Decryption Register Register59427 MemoryManagementandProtectionUnits(MMU,M PU) Functional PID Embedded External Peripheral60828 Process ID controller (PID) Functional Interrupt Information Proactive Process Register Registers61529 On Chip Sensors and Analog Signal Capacitive Touch Available Functional Touch SAR Introduction621 Espressif Systems13 Submit