Odyssey Bluetooth SMART Sensor Board Teardown
To make it easier to understand the engineering that's gone into the Odyssey Bluetooth SMART Sensor board, we decided to tear down the board and go through the key components. For a schematic of the design, [click here]
[Full disclosure: We sell the devices shown here, so if you have a design that you expect to drive volume, please contact us so we can guide you to the best part for your application.]
Main Processing Elements
Broadcom BCM20737S Bluetooth SMART (BLE) Module
The BCM20737S from Broadcom gives the board its wireless connectivity. The module is a Bluetooth Low Energy (BLE/Bluetooth SMART) module that includes the BLE radio, an onboard ARM Corex-M3 processor, memory, and peripherals making it an all-in-one solution for BLE connected devices and wearables. It supports an easy-to-use embedded stack for host and controller functions and includes full capability for developing and implementing new profiles and applications. In addition to an onboard stack and profiles, this 6.5 x 6.5 SIP Module includes BT SMART Transceiver, Crystal, EEPROM, Antenna, Passives, and Regulatory approvals as well. The module uses a development environment called the WICED Smart SDK which can be downloaded from Broadcom's community portal, here. The people at Mpression appreciate if a Macnica distributor (Macnica Americas or Tecstar) is selected when Odyssey customers sign up for community access!
To visit the Broadcom Community for more Bluetooth SMART information: [click here]
Silicon Labs EFM32GG395F512 Low-Power Giant Gecko 32-bit Microcontroller
The EFM32 low-power Giant Gecko microcontroller provides the USB interface and acts as the programmer/debug port for the Broadcom Bluetooth SMART (BCM20737S) module. It also manages the loading of the MAX 10 FPGA if you purchased the kit that includes the MAX 10 FPGA board. In addition, it enables loading of new "personalities" into the flash memory on the Odyssey board so users can leverage the Mpression smartphone app in their custom designs. Certain sensor functions are also enabled by this processor.
For more information on Silicon Labs EFM32 Giant Gecko controllers: [click here]
Cypress CY62148 4MB SRAM
The CY62148EV30 is a 4-Mbit MoBL® SRAM that serves as an expansion memory for the EFM32 microcontroller to support FPGA JTAG loading (JAM player, which is a very memory-intensive function). The CY62148EV30 is designed for extending battery life in portable devices, with ultra-low active current and an automatic power-down feature that that consumes only 1uA typical standby current. Cypress is well known for its broad array of reliable, high-performance SRAMs and nonvolatile RAMs used in mission-critical systems.
Product information on CY62148EV30: [click here]
Micron M25PX16 Flash
The M25PX16 is a 16Mbit NOR SPI flash from Micron used to store "personality" information on the Odyssey board. The device is controlled from the EFM32 and features an operating voltage down to 2.3V and deep powerdown current of 10uA max.
For details on the M25PX16 flash: [click here]
Enpirion EP5358 Power Regulator
The EP5358HUI PowerSoC is a tiny DC-DC switching regulator with built-in inductor. It provides up to 600mA of power to the Odyssey board from the USB port at up to 93% efficiency which helps to avoid heating the nearby humidity/temp sensor. Requiring only an input and an output capacitor, the EP5358HUI achieves a tiny 14 mm2 footprint while being extremely easy to use.
For information on the whole family of space-conscious PowerSoCs [click here]
Linear Technology LTC4415 Dual Ideal Diode / Powerpath Controller
The LTC4415 is a dual ideal diode allowing power to be switched seamlessly between the coin cell battery and the USB source without the voltage drop associated with diode-or'ing.
Linear Technology also has a number of other interesting options for the IoT market, such as their energy harvesting solutions: [click here]
Wurth WE-TVS Diode
It's always important to protect high speed data lines such as the cabled USB 2.0 interface from over-voltage caused by Electrostatic Discharge (ESD), Electrical Fast Transients (EFT) and lightning strikes (Surge). Although not officially a power component, the Odyssey board utilizes the Wurth Elektronik WE-TVS Diode array to provide protection for the USB port lines with very low (<2pf) capacitance.
Wurth has a good application note on the subject of USB protection: USB Port Protection
Analog Devices ADXL362 Accelerometer
The ADXL362 accelerometer allows the board to detect and report motion to the smartphone app based on a threshold set by the user.
The ADXL362 3-axis accelerometer is one of the lowest power in the industry at less than 2µA @ 100Hz sampling, and also includes a unique mode allowing motion-triggered wake up which operates at an amazing 270 nano Amps. This allows a system to be designed such that it is optionally powered down completely until motion is detected, saving battery power.
For more Analog Devices ADXL362 product info [click here]
Silicon Labs Si7020 Temperature/Humidity Sensor
The Si7020 allows the Odyssey to measure temperature and relative humidity and report the values via the I2C interface. It's factory calibrated and available with an optional factory-installed protective cover. And like everything else on Odyssey, it's tiny. It is the primary component used in the following pre-loaded personality:
For further Si7020 product information, [click here]
Silicon Labs Si1147 Proximity/UV/Ambient Light/Heart Rate Monitor Sensor
The Si1147 provides a variety of sensor functions including measuring UV levels, ambient light, proximity and gestures, heart rate, and blood oximetry. The data is communicated over the I2C interface. It is the primary component used in the following pre-loaded personalities:
- UV/Ambient Light
- Proximity and 2D Gesture
- Heart Rate Monitor
For further Si1147 product information, [click here]
The SiT1532 provides the 32 kHz oscillator input to the Energy Micro device. This devices uses SiTime's silicon MEMS technology, which replaces a quartz crystal. The SiT1532 oscillator enables greater component placement flexibility and eliminates external load capacitors, thus saving additional component count and board space, and its NanoDrive™ factory programmable output can reduce the voltage swing to minimize power. The SiT1532 oscillator is ideal in battery powered applications such as Odyssey.
For further SiT1532 information: [click here]