The Dash v1.2 is a fully open source reference design and prototyping platform for developers to rapidly test and move applications to market. The Dash helps developers makes connectivity simple and enables embedded applications to interface with other peripherals and sensors through an array of GPIO, serial interfaces, and analog pins. The on-board microcontrollers and battery management ICs make the Dash are ideal for low-power, low data usage applications.
Note: The Hologram Dash is no longer in production.
System block diagram
Pinout diagram
Microcontrollers
The Dash uses two microcontrollers:
The System microcontroller is Freescale's MKL17Z256VFM4 which features a 32-bit ARM Cortex-M0+ that runs at 48 MHz and has 256 kB Flash and 32 kB RAM. This microcontroller manages the u-blox modem as well as connections into Hologram's cloud.
User microcontroller
The User microcontroller is Freescale's MK22FN1M0AVLH12 which features a 32-bit ARM Cortex-M4 that runs at 120MHz and has 1MB Flash and 256kB RAM. This microcontroller exclusively hosts user programs that are fully compatible with Arduino APIs. (Note: although our firmware is fully Arduino-compatible, when loading Arduino libraries on the Dash, it is important to check the library for hardware-specific calls. In these cases these libraries will not be compatible with the Dash out of the box.)
- Open source User microcontroller firmware
- Datasheet for the MK22FN1M0AVLH12
- Reference sheet for the MK22FN1M0AVLH12
Open source hardware
Hologram is committed to providing open source hardware to enable developers looking for a field-tested and readily scalable reference design.
The Dash v1.2 is certified by the OSHWA (Open Source Hardware Association) under identifier US000082. The design can be modified and adapted to any application (commercial or otherwise).
https://github.com/HologramEducation/dash-hardware
Power Input/Output Characteristics
The Dash v1.2 can be powered using the USB5V, VBATT, or SystemVin pins. The Dash v1.2 can power other peripherals through the VSystemUser and 3.3V pins. Allowable minimum and maximum voltage and current for these power inputs and power outputs is listed below.
| Symbol | Description | Min | Typical | Max |
|---|---|---|---|---|
| USB_5V | USB 5V input | 4.75V | 5V | 5.25V / 2.1A |
| VBATT | Battery input | 2.0V @ 0.1mA | 4.2V | 200mA |
| 3.3V | 3.3V output | 3.3V | 3.32V / 250mA | |
| SystemVin | 5V input | 4.75V | 5V | 7V / 1.8A |
| VSystem_User | 5V output | VSystem-.7* / 250mA** |
*System_User is a reference to the internal 5V power supply, protected by an input diode.
** Current draw by peripherals on this pin should be limited to 250mA to maintain normal operation of internal Dash components.
Peripherals and GPIO
Peripherals and GPIO on the Dash v1.2 minimum and maximum voltages are listed below. The Dash user microcontroller works at 3.3V (i.e. 3.3V registers as a “1” for digital GPIO and analog input) and the digital pins are 5V tolerant whereas the analog pins are 4.1V tolerant.
| # of pins | Input/Output | Min | Max | |
|---|---|---|---|---|
| DIGITAL GPIO | 25 | Both | -0.3 | 5.5V |
| ADC | 10 | Input | -0.3 | 4.1V |
| DAC | 1 | Output | 0 | 3.3V |
| I2C | 2 | Both | -0.3 | 5.5V |
| UART | 2 | Both | -0.3 | 5.5V |
| SPI | 2* | Both | -0.3 | 5.5V |
| CAN | 1 | Both | -0.3 | 5.5V |
*Denotes single SPI with 2 configurations
Power management
Deep sleep
The Dash has three different power operating modes that are configurable via API:
- Normal (default): Both microcontrollers are running at standard clock rates (48MHz and 120MHz for the System and User microcontrollers, respectively) and the u-blox modem is on. The User modem can be configured for 120MHz, 100MHz, or 48MHz.
- Sleep: Instruction clock is paused and peripherals and interrupts remain active.
- deepSleep: Lowest possible power mode on the Dash. Most peripherals and interrupts are disabled, only select wake-up interrupts can wake from deepSleep (select I/O pins, alarm) when configured. The system microcontroller, user microcontroller, and u-blox modem can be placed into deepSleep independently. Hologram has verified, lab-observed deepSleep current of 350uA.
Battery charging
Battery charging is automatically managed by the MCP73871-2CCI/ML IC.
The details for the MCP73871-2CCI/ML can be found on the datasheet.
Radio specifications
The Dash v1.2 features the global band SARA-U201 or the global band SARA-R410M depending on 3G/2G or Cat-M/NB-IoT variant, respectively. Both of these modems are considered global band and work anywhere we have 2G/3G or Cat-M1 coverage, respectively.
The SARA-U201 modem supports a global list of 2G and 3G frequencies:
3G Bands
- Americas: Band 5 (850MHz), Band 2 (1900MHz)
- Europe/Asia/Africa: Band 8 (900MHz), Band 1 (2100MHz)
2G Bands
- GSM - 850MHz
- E-GSM - 900MHz
- DCS - 1800 MHz
- PCS - 1900 MHz
The SARA-R410M modem supports a global list of Cat-M1 and NB-IoT bands:
- 1, 2, 3, 4, 5, 8, 12, 13, 17, 18, 19, 20, 25, 26, 28 (and band 39 in M1-only)
These bands correspond to Uplink and Downlink frequencies in the following ranges (in MHz):
- 700, 800, 850, 900, 1700, 1800, 1900, 2100
The full list of bands and frequencies can be found in the u-blox SARA datasheet.
Mechanical dimensions
LEDs and buttons
The Dash includes 3 different LEDS and two different buttons:
Reset Button:Resets the user microcontroller.
Program Button:used to put Dash into programming mode.
Program LED:flashes when the Dash is in programming mode
User LED:full configurable by user programs using the Arduino IDE
RGB LED:configurable by user programs
Read more about configuring both User and RGB LEDs in our Dash API reference.
Antenna
The Dash is made for ultimate flexibility and this extends to the antenna. The stock black antenna has the following characteristics:
- Size(main radiator): 2cm x 7cm
- Size(cable length): 10cm
- Connector:UFL
- Mounting:Adhesive 3M tape
- Temperature:-40C - +85C
- VSWR:824MHz - 960MHz: < 3 | 1710MHz - 2170MHz: < 3
- Impedance:50ohm
Bill of materials
| Designator | Comment | MPN |
|---|---|---|
| ANT_UFL | ANT-A-1JB | A-1JB |
| J20 | BAT_TERM_TOP_ENTRY | B2B-PH-SM4-TB(LF)(SN) |
| C2, C3, C4, C6, C7, C8, C9, C12, C14, C15, C18, C24, C25, C26, C48 | 0.1 uF | GRM155R61C104KA88D |
| C16, C20, C49 | 1 uF | 04026D105KAT2A |
| C1 | 1 uF | GRM188R71C105KA12D |
| C10, C11, C13, C28 | 2.2 uF | CL10A225MQ8NNNC |
| C27, C39 | 10 nF | GRM155R71C103KA01D |
| C33, C34 | 10 uF | GRM188R60J106ME84D |
| C46 | 15 pf | 04025A150JAT2A |
| C36, C37, C38 | 22 uF | GRM188R60J226MEA0D |
| C41, C42, C44, C45 | 47 pF | 04025A470JAT2A |
| C40 | 56 pf | C0402C560J5GACTU |
| C47 | 330uF | F950J337MBAAQ2 |
| X1 | CRYSTAL_16MHz | CX2016DB16000D0WZRC1 |
| X2, X3 | 32.768 kHz | ABS05-32.768KHZ-T |
| D8 | CDBQR0230L | CDBQR0230L |
| U3, U4 | CDBQR0230L | CRS08(TE85L,Q,M) |
| L1, L2, L3, L7 | FerriteBead_220ohm | BLM18AG121SN1D |
| U6 | FREESCALE_MKL17Z256VFM4 | MKL17Z256VFM4 |
| F6 | 3A | SF-0603S300-2 |
| L5 | 1uH | XFL4020-102MEC |
| D1, D7 | LED_0402_VLMW | VLMW1500-GS08 |
| D2 | LED_RGB_1mm_sq | SMLP34RGB2W3 |
| U19 | MAX1704X | MAX17043G+U |
| U1 | MICROCHIP_73871 | MCP73871-2CCI/ML |
| U5 | MK22FN1M0VLH12 | MK22FN1M0AVLH12 |
| U10 | NCP177AMX330TCG | |
| D3, D4, D5, D6, D9, D10, D11 | PESD0402-140 | |
| JLEFT, JRIGHT | MOLEX | |
| R66 | 0 | ERJ-2GE0R00X |
| R45 | 1k | RC0402JR-071KL |
| R13 | 1M | RC0402FR-071ML |
| R8 | 2k | RC0402FR-072KL |
| R24, R35, R36, R37, R38, R40, R47, R2000 | 10K | RC0402JR-0710KL |
| R1, R2 | 22 | RC0402FR-0722RL |
| R7 | 62k | RC0402FR-0762KL |
| R26, R65 | 75 | RC0402FR-0775RL |
| R51 | 100K | ERJ-2GEJ104X |
| R21 | 120 | ERJ-2GEJ121X |
| R12 | 150k | RC0402FR-07150KL |
| R22 | 160 | ERJ-2GEJ161X |
| R19, R20 | 470 | ERJ-2GEJ471X |
| U420 | SARA-U2XX | SARA-U201-00S |
| SIM1 | SIM_CARD_NANO | SIM8050-6-0-14-01-A |
| SW1, SW2 | SWITCH_PTS810 | PTS810 SJM 250 SMTR LFS |
| U9 | TPS22945DCKR | |
| U2 | TPS63020 | TPS63020DSJ |
| J1 | Micro USB B FCI 10118193 | 10118193-0001LF |
| U8 | VOLTAGE_TRANSLATOR_4_BIT | SN74AVC4T774RSVR |