ESPRESSIF ESP32 Wrover-e Bluetooth Low Energy Module User Manual

ESP32-WROVER-E &
ESP32-WROVER-IE
User Manual

 Overview

ESP32-ROVER-E is a powerful, generic WiFi-BT-BLE MCU module that targets a wide variety of applications, ranging from low-power sensor networks to the most demanding tasks, such as voice encoding, music streaming, and MP3 decoding.
This module is provided in two versions: one with a PCB antenna, the other with an IPEX antenna. ESP32WROVER-E features a 4 MB external SPI flash and an additional 8 MB SPI Pseudo static RAM (PSRAM). The information in this datasheet is applicable to both modules. The ordering information on the two variants of ESP32-WROVER-E is listed as follows:

(18.00±0.10)×(31.40±0.10)×(3.30±0.10)
ESP32-WROVER-IE (IPEX)
Notes:
ESP32-ROVER-E (PCB) or ESP32-ROVER-IE(IPEX) with 4 MB flash or 16 MB flash is available for
1.  custom order.
2.  For detailed ordering information, please se e Espressif Product Ordering Inform ation.
3.  For dimensions of the IPEX connector, please see Chapter 10.

Table 1: ESP32-ROVER-E Ordering Information

At the core of the module is the ESP32-D0WD-V3 chip*. The chip embedded is designed to be scalable and adaptive. There are two CPU cores that can be individually controlled, and the CPU clock frequency is adjustable from 80 MHz to 240 MHz. The user may also power off the CPU and make use of the low-power co-processor to constantly monitor the peripherals for changes or crossing of thresholds. ESP32 integrates a rich set of peripherals, ranging from capacitive touch sensors, Hall sensors, SD card interface, Ethernet, high- speed SPI, UART, I²S, and I²C.

Note:

• For details on the part numbers of the ESP32 family of chips, please refer to the document ESP32 User Manua l.

The integration of Bluetooth, Bluetooth LE, and Wi-Fi ensures that a wide range of applications can be targeted and that the module is all-around: using Wi-Fi allows a large physical range and direct connection to the Internet through a Wi-Fi router while using Bluetooth allows the user to conveniently connect to the phone or broadcast low energy beacons for its detection. The sleep current of the ESP32 chip is less than 5 A, making it suitable for battery-powered and wearable electronics applications. The module supports a data rate of up to 150 Mbps. As such the module does offer industry-leading specifications and the best performance for electronic integration, range, power consumption, and connectivity.

The operating system chosen for ESP32 is freeRTOS with LwIP; TLS 1.2 with hardware acceleration is built-in as well. Secure (encrypted) over the air (OTA) upgrade is also supported, so that users can upgrade their products even after their release, at minimum cost and effort.
Table 2 provides the specifications of ESP32-ROVER-E.

Table 2: ESP32-WROVER-E Specifications

A-MPDU and A-MSDU aggregation and 0.4 s guard in- terval support
Frequency range| 2412-2462MHz
Bluetooth| Protocols| Bluetooth v4.2 BR/EDR and BLE specification

Radio

| NZIF receiver with –97 dBm sensitivity
Class-1, class-2 and class-3 transmitter
AFH
Audio| CVSD and SBC
Hardware|

Module interfaces

| SD card, UART, SPI, SDIO, I2C, LED PWM, Motor PWM, I2S, IR, pulse counter, GPIO, capacitive touch sensor, ADC, DAC
On-chip sensor| Hall sensor
Integrated crystal| 40 MHz crystal
Integrated SPI flash| 4 MB
Integrated PSRAM| 8 MB
Operating voltage/Power supply| 3.0 V ~ 3.6 V
Minimum current delivered by the power supply| 500 mA
Recommended operating temperature range| –40 °C ~ 65 °C
size| (18.00±0.10) mm × (31.40±0.10) mm × (3.30±0.10) mm
Moisture sensitivity level (MSL)| Level 3

 Pin Definitions

2.1 Pin Layout

Pin Description

ESP32-ROVER-E has 38 pins. See pin definitions in Table 3.

Table 3: Pin Definitions

ADC1_CH4, TOUCH9, RTC_GPIO9
IO33| 9| I/O| GPIO33, XTAL_32K_N (32.768 kHz crystal oscillator output), ADC1_CH5, TOUCH8, RTC_GPIO8
IO25| 10| I/O| GPIO25, DAC_1, ADC2_CH8, RTC_GPIO6, EMAC_RXD0
IO26| 11| I/O| GPIO26, DAC_2, ADC2_CH9, RTC_GPIO7, EMAC_RXD1
IO27| 12| I/O| GPIO27, ADC2_CH7, TOUCH7, RTC_GPIO17, EMAC_RX_DV
IO14| 13| I/O| GPIO14, ADC2_CH6, TOUCH6, RTC_GPIO16, MTMS, HSPICLK, HS2_CLK, SD_CLK, EMAC_TXD2
IO12| 14| I/O| GPIO12, ADC2_CH5, TOUCH5, RTC_GPIO15, MTDI, HSPIQ, HS2_DATA2, SD_DATA2, EMAC_TXD3
GND| 15| P| Ground
IO13| 16| I/O| GPIO13, ADC2_CH4, TOUCH4, RTC_GPIO14, MTCK, HSPID, HS2_DATA3, SD_DATA3, EMAC_RX_ER
NC| 17| –| –
NC| 18| –| –
NC| 19| –| –
NC| 20| –| –
NC| 21| –| –
NC| 22| –| –
IO15| 23| I/O| GPIO15, ADC2_CH3, TOUCH3, MTDO, HSPICS0, RTC_GPIO13, HS2_CMD, SD_CMD, EMAC_RXD3
IO2| 24| I/O| GPIO2, ADC2_CH2, TOUCH2, RTC_GPIO12, HSPIWP, HS2_DATA0, SD_DATA0
IO0| 25| I/O| GPIO0, ADC2_CH1, TOUCH1, RTC_GPIO11, CLK_OUT1, EMAC_TX_CLK
IO4| 26| I/O| GPIO4, ADC2_CH0, TOUCH0, RTC_GPIO10, HSPIHD, HS2_DATA1, SD_DATA1, EMAC_TX_ER
NC1| 27| –| –
NC2| 28| –| –
IO5| 29| I/O| GPIO5, VSPICS0, HS1_DATA6, EMAC_RX_CLK
IO18| 30| I/O| GPIO18, VSPICLK, HS1_DATA7
Name| No.| Type| Function
---|---|---|---
IO19| 31| I/O| GPIO19, VSPIQ, U0CTS, EMAC_TXD0
NC| 32| –| –
IO21| 33| I/O| GPIO21, VSPIHD, EMAC_TX_EN
RXD0| 34| I/O| GPIO3, U0RXD, CLK_OUT2
TXD0| 35| I/O| GPIO1, U0TXD, CLK_OUT3, EMAC_RXD2
IO22| 36| I/O| GPIO22, VSPIWP, U0RTS, EMAC_TXD1
IO23| 37| I/O| GPIO23, VSPID, HS1_STROBE
GND| 38| P| Ground

Notice:

• GPIO6 to GPIO11 are connected to the SPI flash integrated on the module and are not connected out.

Strapping Pins

ESP32 has five strapping pins, which can be seen in Chapter 6 Schematics:

• MDI
• GPIO0
• GPIO2
• MTDO
• GPIO5

The software can read the values of these five bits from the register ”GPIO_STRAPPING”.
During the chip’s system reset release (power-on-reset, RTC watchdog reset, and brownout reset), the latches of the strapping pins sample the voltage level as strapping bits of ”0” or ”1”, and hold these bits until the chip is powered down or shut down. The strapping bits configure the device’s boot mode, the operating voltage of VDD_SDIO and other initial system settings.

Each strapping pin is connected to its internal pull-up/pull-down during the chip reset. Consequently, if a strapping pin is unconnected or the connected external circuit is high-impedance, the internal weak pull-up/pull-down will determine the default input level of the strapping pins.
To change the strapping bit values, users can apply the external pull-down /pull-up resistances, or use the host MCU’s GPIOs to control the voltage level of these pins when powering on ESP32.
After reset release, the strapping pins work as normal-function pins. Refer to Table 4 for a detailed boot-mode configuration by strapping pins.
Table 4: Strapping Pins

The voltage of Internal LDO (VDD_SDIO)

Pin| Default| 3.3 V| 1.8 V
MDI| Pull-down| 0| 1
Booting Mode

Pin| Default| SPI Boot| Download Boot
GPIO0| Pull-up| 1| 0
GPIO2| Pull-down| Don’t-care| 0
Enabling/Disabling Debugging Log Print over U0TXD During Booting
Pin| Default| U0TXD Active| U0TXD Silent
MTDO| Pull-up| 1| 0
Timing of SDIO Slave
Pin| Default| Falling-edge Sampling
Falling-edge Output| Falling-edge Sampling
Rising-edge Output| Rising-edge Sampling
Falling-edge Output| Rising-edge Sampling
Rising-edge Output
MTDO| Pull-up| 0| 0| 1| 1
GPIO5| Pull-up| 0| 1| 0| 1

Note:

• Firmware can configure register bits to change the settings of ”Voltage of Internal LDO (VDD_SDIO)” and ”Timing of SDIO Slave” after
• The internal pull-up resistor (R9) for MTDI is not populated in the module, as the flash and SRAM in ESP32- ROVER-E only support a power voltage of 3 V (output by VDD_SDIO)

1.        Functional Description

This chapter describes the modules and functions integrated into ESP32-ROVER-E.

CPU and Internal Memory

ESP32-D0WD-V3 contains two low-power Xtensa® 32-bit LX6 microprocessors. The internal memory includes:

• 448 KB of ROM for booting and core
• 520 KB of on-chip SRAM for data and
• 8 KB of SRAM in RTC, which is called RTC FAST Memory and can be used for data storage; it is accessed by the main CPU during RTC Boot from the Deep-sleep
• 8 KB of SRAM in RTC, which is called RTC SLOW Memory and can be accessed by the co-processor during the Deep-sleep
• 1 Kbit of use: 256 bits are used for the system (MAC address and chip configuration) and the remaining 768 bits are reserved for customer applications, including flash-encryption and chip-ID.

External Flash and SRAM

ESP32 supports multiple external QSPI flash and SRAM chips. More details can be found in Chapter SPI in the ESP32 Technical Reference Manua l. ESP32 also supports hardware encryption/decryption based on AES to protect developers’ programs and data in flash.
ESP32 can access the external QSPI flash and SRAM through high-speed caches.

• The external flash can be mapped into CPU instruction memory space and read-only memory space simultaneously.
  • When the external flash is mapped into CPU instruction memory space, up to 11 MB + 248 KB can be mapped at a time. Note that if more than 3 MB + 248 KB are mapped, cache performance will be reduced due to speculative reads by the
  • When the external flash is mapped into read-only data memory space, up to 4 MB can be mapped at an 8-bit, 16-bit, and 32-bit reads are supported.
• External SRAM can be mapped into CPU data memory space. Up to 4 MB can be mapped at a time. 8- bit, 16-bit, and 32-bit reads and writes are

ESP32-ROVER-E integrates an 8 MB SPI flash and an 8 MB PSRAM for more memory space.

Crystal Oscillators

The module uses a 40-MHz crystal oscillator.

RTC and Low-Power Management

With the use of advanced power-management technologies, ESP32 can switch between different power modes.
For details on ESP32’s power consumption in different power modes, please refer to the section ”RTC and Low- Power Management” in ESP32 Datas heet.

Peripherals and Sensors

Please refer to Section Peripherals and Sensors in ESP32 User, Man ua l.

Note:
External connections can be made to any GPIO except for GPIOs in the range 6-11, 16, or 17. GPIOs 6-11 are connected to the module’s integrated SPI flash and PSRAM. GPIOs 16 and 17 are connected to the module’s integrated PSRAM. For details, please see Section 6 Schematics.

1.        Electrical Characteristics

Absolute Maximum Ratings

Stresses beyond the absolute maximum ratings listed in the table below may cause permanent damage to the device. These are stress ratings only and do not refer to the functional operation of the device that should follow the recommended operating conditions.

Table 5: Absolute Maximum Ratings

1. The module worked properly after a 24-hour test in ambient temperature at 25 °C, and the IOs in three domains (VDD3P3_RTC, VDD3P3_CPU, VDD_SDIO) output high logic level to the ground. Please note that pins occupied by flash and/or PSRAM in the VDD_SDIO power domain were excluded from the
2. Please see Appendix IO_MUX of ESP32 Datashee t for IO’s power

 Recommended Operating Conditions

Table 6: Recommended Operating Conditions

Symbol

| Parameter| Min| Typical| Max|

Unit

---|---|---|---|---|---
VDD33| Power supply voltage| 3.0| 3.3| 3.6| V
IVDD| Current delivered by the external power supply| 0.5| –| –| A
T| Operating temperature| –40| –| 65| °C

DC Characteristics (3.3 V, 25 °C)

Table 7: DC Characteristics (3.3 V, 25 °C)

Symbol

| Parameter| Min| Typ| Max|

Unit

---|---|---|---|---|---
C IN| Pin capacitance| –| 2| –| pF
V IH| High-level input voltage| 0.75×VDD1| –| VDD1+0.3| V
V IL| Low-level input voltage| –0.3| –| 0.25×VDD1| V
II| High-level input current| –| –| 50| nA
II| Low-level input current| –| –| 50| nA
V OH| High-level output voltage| 0.8×VDD1| –| –| V
V OL| Low-level output voltage| –| –| 0.1×VDD1| V

I OH

| High-level source current (VDD1 = 3.3 V, V OH >= 2.64 V, output drive strength set to the maximum)| VDD3P3CPU power domain 1 ;_ 2| –| 40| –| mA
VDD3P3RTC power domain 1 ;_ 2| –| 40| –| mA
VDDSDIO power domain 1 ;_ 3|

–

|

20

|

–

|

mA

Symbol

| Parameter| Min| Typ| Max|

Unit

---|---|---|---|---|---
I OL| Low-level sink current (VDD1 = 3.3 V, V OL = 0.495 V, output drive strength set to the maximum)|

–

|

28

|

–

|

mA

R P U| Resistance of internal pull-up resistor| –| 45| –| kΩ
R P D| Resistance of internal pull-down resistor| –| 45| –| kΩ
V IL _ nRST| Low-level input voltage of CHIP_PU to power off the chip| –| –| 0.6| V

Notes:

1. Please see Appendix IO_MUX of ESP32 Datasheet for IO’s power domain. VDD is the I/O voltage for a particular power domain of
2. For VDD3P3_CPU and VDD3P3_RTC power domain, per-pin current sourced in the same domain is gradually reduced from around 40 mA to around 29 mA, V OH >=2.64 V, as the number of current-source pins
3. Pins occupied by flash and/or PSRAM in the VDD_SDIO power domain were excluded from the

Wi-Fi Radio

Table 8: Wi-Fi Radio Characteristics

dBm

Sensitivity| 11b, 1 Mbps| –| –98| –| dBm
11b, 11 Mbps| –| –89| –| dBm
11g, 6 Mbps| –| –92| –| dBm
11g, 54 Mbps| –| –74| –| dBm
11n, HT20, MCS0| –| –91| –| dBm
11n, HT20, MCS7| –| –71| –| dBm
11n, HT40, MCS0| –| –89| –| dBm
11n, HT40, MCS7| –| –69| –| dBm
Adjacent channel rejection| 11g, 6 Mbps| –| 31| –| dB
11g, 54 Mbps| –| 14| –| dB
11n, HT20, MCS0| –| 31| –| dB
11n, HT20, MCS7| –| 13| –| dB

1. The device should operate in the frequency range allocated by regional regulatory authorities. Target operating frequency range is configurable by
2. For the modules that use IPEX antennas, the output impedance is 50 Ω. For other modules without IPEX antennas, users do not need to be concerned about the output
3. Target TX power is configurable based on device or certification

Bluetooth/BLE Radio

Receiver

Table 9: Receiver Characteristics – Bluetooth/BLE

  Transmitter

Table 10: Transmitter Characteristics – Bluetooth/BLE

Reflow Profile

Figure 2: Reflow Profile

 Learning Resources

Must-Read Documents

The following link provides documents related to ESP32.

• ESP32 User Manua l

This document provides an introduction to the specifications of the ESP32 hardware, including an overview, pin definitions, functional description, a peripheral interface, electrical characteristics, etc.

• ESP-IDF Programming Guide

It hosts extensive documentation for ESP-IDF ranging from hardware guides to API reference.

• ESP32 Technical Reference Manua l

The manual provides detailed information on how to use the ESP32 memory and peripherals.

• ESP32 Hardware Resources

The zip files include the schematics, PCB layout, Gerber, and BOM list of ESP32 modules and development boards.

• ESP32 Hardware Design Guidelines

The guidelines outline recommended design practices when developing standalone or add-on systems based on the ESP32 series of products, including the ESP32 chip, the ESP32 modules, and development boards.

• ESP32 AT Instruction Set and Examples

This document introduces the ESP32 AT commands, explains how to use them, and provides examples of several commons AT commands.

• Espressif Products Ordering Information

Must-Have Resources

Here are the ESP32-related must-have resources.

• ESP32 BBS

This is an Engineer-to-Engineer (E2E) Community for ESP32 where you can post questions, share knowledge, explore ideas, and help solve problems with fellow engineers.

• ESP32 GitHub

ESP32 development projects are freely distributed under Espressif’s MIT license on GitHub. It is established to help developers get started with ESP32 and foster innovation and the growth of general knowledge about the hardware and software surrounding ESP32 devices.

• ESP32 Tools

This is a webpage where users can download ESP32 Flash Download Tools and the zip file ”ESP32 Certification and Test”.

• ESP-IDF

This webpage links users to the official IoT development framework for ESP32.

• ESP32 Resources

This webpage provides the links to all available ESP32 documents, SDK, and tools.

OEM Guidance

1. Applicable FCC rules
   This module is granted by Single Modular Approval. It complies with the requirements of FCC part 15C, section 15.247 rules.

2. The specific operational use conditions
   This module can be used in IoT devices. The input voltage to the module is nominal 3.3V-3.6 V DC. The operational ambient temperature of the module is –40 °C ~ 65 °C. Only the embedded PCB antenna is allowed. Any other external antenna is prohibited.

3. Limited module procedures N/A

4. Trace antenna designN/A

5. RF exposure considerations
   The equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with a minimum distance of 20cm between the radiator and your body. If the equipment is built into a host as a portable usage, the additional RF exposure evaluation may be required as specified by 2.1093.

6. Antenna
   Antenna type: PCB antenna    Peak gain: 3.40dBi Omni antenna with IPEX connector Peak gain2.33dBi

7. Label and compliance information
   An exterior label on OEM’s end product can use wording such as the following: “Contains Transmitter Module FCC ID: 2AC7Z-ESP32WROVERE” or “Contains FCC ID: 2AC7Z-ESP32WROVERE.”

8. Information on test modes and additional testing requirements
   a)The modular transmitter has been fully tested by the module grantee on the required number of channels, modulation types, and modes, it should not be necessary for the host installer to re-test all the available transmitter modes or settings. It is recommended that the host product manufacturer, installing the modular transmitter, perform some investigative measurements to confirm that the resulting composite system does not exceed the spurious emissions limits or band edge limits (e.g., where a different antenna may be causing additional emissions).
   b)The testing should check for emissions that may occur due to the intermixing of emissions with the other transmitters, digital circuitry, or physical properties of the host product (enclosure). This investigation is especially important when integrating multiple modular transmitters where the certification is based on testing each of them in a stand-alone configuration. It is important to note that host product manufacturers should not assume that because the modular transmitter is certified that they do not have any responsibility for final product compliance.
   c)If the investigation indicates a compliance concern the host product manufacturer is obligated to mitigate the issue. Host products using a modular transmitter are subject to all the applicable individual technical rules as well as to the general conditions of operation in Sections 15.5, 15.15, and 15.29 to not cause interference. The operator of the host product will be obligated to stop operating the device until the interference has been corrected .

9. Additional testing, Part 15 Subpart B disclaimer The final host/module combination needs to be evaluated against the FCC Part 15B criteria for unintentional radiators in order to be properly authorized for operation as a Part 15 digital device. The host integrator installing this module into their product must ensure that the final composite product complies with the FCC requirements by a technical assessment or evaluation of the FCC rules, including the transmitter operation, and should refer to the guidance in  KDB 996369. For host products with the certified modular transmitter, the frequency range of investigation of the composite system is specified by a rule in Sections 15.33(a)(1)  through (a)(3), or the range applicable to the digital device, as shown in Section 15.33(b)(1), whichever is the higher frequency range of investigation When testing the host product, all the transmitters must be operating. The transmitters can be enabled by using publicly available drivers and turned on, so the transmitters are active. In certain conditions, it might be appropriate to use a technology-specific call box (test set) where accessory 50 devices or drivers are not available. When testing for emissions from the unintentional radiator, the transmitter shall be placed in the receive mode or idle mode, if possible. If receive mode only is not possible then, the radio shall be passive  (preferred) and/or active scanning. In these cases, this would need to enable activity on the communication BUS (i.e., PCIe, SDIO, USB) to ensure the unintentional radiator circuitry is enabled. Testing laboratories may need to add attenuation or filters depending on the signal strength of any active beacons (if applicable) from the enabled radio(s). See ANSI C63.4, ANSI C63.10, and ANSI C63.26 for further general testing details.
   The product under test is set into a link/association with a partnering device, as per the normal intended use of the product. To ease testing, the product under test is set to transmit at a high duty cycle, such as by sending a file or streaming some media content.

FCC Warning:
Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any  interference received, including interference that may cause undesired operation

About This Document
This document provides the specifications for the ESP32-ROVER-E and ESP32 -ROVER-IE modules.

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Information in this document, including URL references, is subject to change without notice. THIS DOCUMENT IS PROVIDED AS-IS WITH NO WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY, NON-INFRINGEMENT, FITNESS FOR ANY PARTICULAR PURPOSE, OR ANY WARRANTY OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE.
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All trade names, trademarks, and registered trademarks mentioned in this document are the property of their respective owners and are hereby acknowledged. Copyright © 2019 Espressif Inc. All rights reserved.

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