gecko-addons:gecko-biomed [Gecko Development Platform]

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<box 300px right | **Project details**>
^ Name: | GECKObiomed ||
^ Maintainer| [[hgb3@bfh.ch]]||
^ Revision: | 1.1 ||
^ Development status: | stable ||
^ Compatibility: | GECKO3 / GECKO4 || 
</box>


===== GECKO-biomed =====

The GECKO-biomed AddOn is a signal processing education board which uses the [[https://www.microlab.ti.bfh.ch/wiki/huce:microlab:projects:internal:microlink:start|micolink]] platform . With the GECKO-biomed a 3-wire ECG can be recorded and displayed. A capacitive touch wheel serves as user input device.
{{ :gecko-addons:front_2.jpg?nolink&200 |}}


<note warning>DO NOT USE USB-POWERED ON GECKO4. It may destroy the power supply of your device!</note>



====== Hardware ======
<note important>Make sure to have distance keeper mounted between the GECKOmain and the GeckoBiomed while using the board to prevent damages on the connectors!</note>
===== Hardware Components =====

=== ECG Front-End ===

To record ECG signals the ADS1194 is used. The ADS1194 includes an analog front end as well as an 16-Bit ADC and needs a minimum of external components.

Features of ADS1194 ([[http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=ads1194&fileType=pdf|Datasheet]]):

  * 4 Low-Noise Programmable Gain Amplifiers
  * Programmable Gain: 1,2,3,4,6,8 or 12
  * 4 16-Bit ADCs
  * Data Rate: 125 SPS up to 8 kSPS
  * CMRR: -105dB
  * Built-In Right Leg Drive Amplifier, Lead-Off Detection, WCT, Test Signals
  * SPI Data Interface
{{ :gecko-addons:gecko-biomed:ads1194_block.jpg?400 |}}

The development of the sensing circuit was done with the ADS1198 evaluation kit ([[http://www.ti.com/lit/ug/sbau180/sbau180.pdf |Datasheet]]). The schematic which is provided in the datasheet was copied and only slightly adapted. The GECKO-biomed AddOn Board uses only 1 Channel of the ADS1194.

ECG-Cable

To record the ECG-Signal a 3 wire cable is used. The cable is connected to the GECKO-biomed by a 3.5mm audio jack.

{{ :gecko-addons:gecko-biomed:41mlvsu9-gl._sl500_aa300_.jpg?nolink&200 |}}

=== Touch Buttons ===

As user input unit capacitive touch buttons are used. The buttons are made by copper layers on the PCB. The used sensing principle is called sigma-delta capacitive sensing.\\ Find detailed information in this paper: {{:gecko3:gecko-addon:gecko-biomed:cypress_capsense_sigma_delta_algorithm_11.pdf|Delta Sigma}}


=== OLED Display ===

To display the ECG-signal a 160 x 128 OLED screen is used:

{{:gecko-addons:gecko-biomed:149884107-40.jpg?nolink&120 |}}
  * Module Name: DD-160128FC-2A
  * Driver IC: SEPS525
  * Mode: OLED RGB
  * Colors: 262 k
  * Data Interface: 6800-/8080-Series MPU
  * Control Interface: SPI
  * Size: 1.69''
  * Resolution: 160 x 128
  * Used Voltage Booster: TPS61080

=== LED's ===

The GECKO-biomed has 4 LED's which are mounted on the backside of the PCB. The LED's can be used as optical feedback.

===== PCB Design =====

PCB design was done by altium designer ECAD. The design files are located in the following directory:
  /mnt/data/fbe/microlab/projekte/intern/GECKO/GECKO_AddOn/GECKO_biomed/04_PCB/Version_1_1
  
For the next revision the power pins on the GPIO 1 have to be adapted to the new specification. 

=== Schematic ===

{{:gecko-addons:gecko-biomed:gecko4biomed_schematic.pdf|gecko_biomed_schem.pdf}}

=== System Bus ===
 
On GECKO-biomed only system bus 1 is used. For this reason GECKO-biomed can be used with GECKO3main and GECKO4main.


=== Powering ===
<note warning>Do not Power the Gecko and the Biomed board over USB only! It will destroy your device.</note>
<note warning>For safety reasons all used GECKO modules have to be powered by battery when recording/displaying an ECG! Don't use an AC wall adapter!</note>

To power a GECKO stack by battery use the GECKO-robot or use a battery powered GECKO-simple!


^Component         ^  3.3 V  ^  3 V  ^  18 V  ^
|OLED Logic         |  ✔   |     |     |     
|OLED Driver        |      |      |    ✔  | 
|Touch Buttons      |  ✔   |     |     |
|ADS1194 Analog     |     |  ✔   |     |
|ADS1194 Interface  |  ✔   |      |     |
|LED's              |  ✔   |      |       |

For 3.3V the +3.3V line from the GECKO system bus 1 is used. 3V and 18V are generated out of VBAT.

=== PCB Layout ===

{{:gecko-addons:gecko-biomed:gecko4biomed_1_1.pdf|gecko_biomed_pcb.pdf}}


=== Final Result ===


{{:gecko-addons:gecko-biomed:front_legend.png?nolink&330 |}}
{{:gecko-addons:gecko-biomed:back_legend.png?nolink&360|}}




====== Pinout ======



==== GECKO system bus 1 (IO-Bus 1)====

<note tip> GECKO-biomed only uses system bus 1. On this bus the signals on GECKO3main and GECKO4main are pin compatible. Select the correct .ucf file for the particular GECKO-main version.</note>



GECKO3main: {{:gecko-addons:gecko-biomed:geckobiomed_gecko_3.ucf|}}

GECKO4main: {{:gecko-addons:gecko-biomed:geckobiomed_gecko_4.ucf|}}


^  Pin   ^     Name       ^   GECKO3main FPGA  ^  GECKO4main FPGA       ^  Description   ^
|  1    |  GND            |        -          |     -         |  System GND  |
|  2    |  GND            |        -          |     -         |  System GND  |
|  4    |  PHI2           |        AF19       |     AC25      |  Switch Signal N-FET       |
|  5    |  GND            |        -          |     -         |  System GND  |
|  6    |  PHI1           |        AE20       |     AC26      |  Switch Signal P-FET       |
|  8    |  GND            |        -          |     -         |  System GND  |
|  11   |  Q_Touch_1      |        AD19       |     Y25       |  Button 1 discharge  |
|  12   |  GND            |        -          |     -         |  System GND  |
|  13   |  Q_Touch_2      |        AE18       |     Y26       |  Button 2 discharge  |
|  14   |  D_Touch_1      |        AD25       |     W25       |  Button 1 output  |
|  15   |  Q_Touch_3      |        AE23       |     W26       |  Button 3 discharge  |
|  16   |  D_Touch_2      |        AC21       |     V25       |  Button 2 output  |
|  17   |  Q_Touch_4      |        AF22       |     U26       |  Button 4 discharge  |
|  18   |  D_Touch_3      |        AC22       |     U25       |  Button 3 output  |
|  19   |  Q_Touch_5      |        AE22       |     T26       |  Button 5 discharge  |
|  20   |  D_Touch_4      |        AB20       |     T25       |  Button 4 output  |
|  21   |  LED4           |        AB17       |     R26       |  LED 4  |
|  22   |  D_Touch_5      |        AB19       |     R25       |  Button 5 output  |
|  23   |  LED3           |        AC19       |     P26       |  LED 3  |
|  25   |  LED2           |        AA25       |     AB23      |  LED 2  |
|  27   |  LED1           |        AB25       |     U20       |  LED 1  |
|  29   |  GND            |        -          |     -         |  System GND  |
|  30   |  GND            |        -          |     -         |  System GND  |
|  33   |  GND            |        -          |     -         |  System GND  |
|  34   |  GND            |        -          |     -         |  System GND  |
|  35   |  VBAT           |        -          |     -         |  Battery Power  |
|  36   |  VBAT           |        -          |     -         |  Battery Power  |
|  37   |  VBAT           |        -          |     -         |  Battery Power  |
|  38   |  VBAT           |        -          |     -         |  Battery Power  |
|  39   |  VBAT           |        -          |     -         |  Battery Power  |
|  40   |  VBAT           |        -          |     -         |  Battery Power  |
|  41   |  GND            |        -          |     -         |  System GND  |
|  42   |  GND            |        -          |     -         |  System GND  |
|  43   |  GND            |        -          |     -         |  System GND  |
|  45   |  GND            |        -          |     -         |  System GND  |
|  46   |  GND            |        -          |     -         |  System GND  |
|  47   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  48   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  49   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  50   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  51   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  52   |  3V3            |        -          |     -         |  System 3.3 V supply  |
|  53   |  GND            |        -          |     -         |  System GND  |
|  54   |  GND            |        -          |     -         |  System GND  |
|  56   |  GND            |        -          |     -         |  System GND  |
|  59   |  GND            |        -          |     -         |  System GND  |
|  60   |  GND            |        -          |     -         |  System GND  |
|  69   |  OLED_BL_EN     |      W25          |     J25       |  OLED Backlight Enable  |
|  70   |  OLED_RESETB    |      W23          |     H26       |  OLED Reset   |
|  71   |  OLED_WRB       |      W22          |     H25       |  OLED Write or Read/Write select  |
|  72   |  OLED_RDB       |      V22          |     D26       |  OLED Read or Read/Write enable  |
|  73   |  OLED_CSB       |      W21          |     D25       |  OLED Chip Select  |
|  74   |  OLED_RS        |      U22          |     N20       |  OLED Data/Command select  |
|  75   |  OLED_D9        |      V21          |     N19       |  OLED Image Data 9   |
|  76   |  OLED_D10       |      R20          |     M20       |  OLED Image Data 10  |
|  84   |  OLED_D11       |      U20          |     U21       |  OLED Image Data 11  |
|  85   |  OLED_D12       |      T20          |     V23       |  OLED Image Data 12  |
|  86   |  OLED_D13       |      R22          |     U22       |  OLED Image Data 13  |
|  87   |  OLED_D14       |      R21          |     V24       |  OLED Image Data 14  |
|  88   |  OLED_D15       |      P22          |     T21       |  OLED Image Data 15  | 
|  89   |  GND            |        -          |     -         |  System GND  |
|  90   |  GND            |        -          |     -         |  System GND  |
|  91   |  OLED_D16       |      P21          |     U23       |  OLED Image Data 16  |
|  92   |  OLED_D17       |      N22          |     T22       |  OLED Image Data 17  |
|  93   |  OLED_PS        |      N21          |     U24       |  OLED Select Interface Type   |
|  94   |  OLED_CPU       |      K22          |     R21       |  OLED Select CPU Type|
|  95   |  OLED_ENABLE    |      L23          |     T23       |  OLED Video Enable  |
|  96   |  OLED_DOTCLK    |      T19          |     R22       |  OLED Dotclock  |
|  97   |  OLED_HSYNC     |      R19          |     R24       |  OLED Horizontal Sync Input  |
|  98   |  OLED_VSYNC     |      P20          |     P21       |  OLED Vertical Sync Input   |
|  99   |  OLED_VSYNCO    |      P19          |     P23       |  OLED Vertical Sync Output   |
|  103  |  ECG_SPI_DRDY   |      M19          |     N24       |  ECG Data Ready       |
|  104  |  ECG_RESET      |      L20          |     N21       |  ECG Chip Reset       |
|  105  |  ECG_SPI_START  |      L19          |     N23       |  ECG Start Conversion |
|  106  |  ECG_PWDN       |      L25          |     M22       |  ECG Power Down       |
|  115  |  ECG_SPI_CLK    |      B10          |     J24       |  ECG SPI clock input  |
|  116  |  ECG_SPI_IN     |      B11          |     K21       |  ECG SPI data in      |
|  117  |  ECG_SPI_OUT    |      A10          |     J23       |  ECG SPI data out     |
|  118  |  ECG_SPI_CS     |      A11          |     J22       |  ECG SPI chip select  |
|  119  |  GND            |        -          |     -         |  System GND  |
|  120  |  GND            |        -          |     -         |  System GND  |

Unlisted pins are unused


GECKO system bus 2 is unused.


===== Software =====

The GeckoBiomed has its own Matlab library. It can be started over the Menu (Applications->Microlab->Others->GeckoBiomed) in your desktop environment.