====== System bus in logical order ======

On this page, the system bus is ordered by the logic blocks of the bus.
===== IO-BUS 1 pins =====
==== Logical blocks ====

^  Pin ^ Block ^ Name    ^ Description           ^
|//Byte 1//||||
|  61  | B1.0 | M1_INA  |  |
|  63  | B1.1 | M1_INB  |  |
|  65  | B1.2 | M2_INA  |  |
|  67  | B1.3 | M2_INB  |  |
|  69  | B1.4 | M3_INA  |  |
|  71  | B1.5 | M3_INB  |  |
|  73  | B1.6 | M4_INA  |  |
|  75  | B1.7 | M4_INB  |  |
|//Byte 2//||||
|  62  | B2.0 | M1_ENA  |  |
|  64  | B2.1 | M1_ENB  |  |
|  66  | B2.2 | M2_ENA  |  |
|  68  | B2.3 | M2_ENB  |  |
|  70  | B2.4 | M3_ENA  |  |
|  72  | B2.5 | M3_ENB  |  |
|  74  | B2.6 | M4_ENA  |  |
|  76  | B2.7 | M4_ENB  |  |
|//Byte 3//||||
|  4   | B3.0 | GPIO1_0  |  |
|  6   | B3.1 | GPIO1_1  |  |
|  11  | B3.2 | GPIO1_2  |  |
|  14  | B3.3 | GPIO1_3  |  |
|  13  | B3.4 | GPIO1_4  |  |
|  16  | B3.5 | GPIO1_5  |  |
|  15  | B3.6 | GPIO1_6  |  |
|  18  | B3.7 | GPIO1_7  |  |
|//Byte 4//||||
|  17  | B4.0 | GPIO1_8  |  |
|  20  | B4.1 | GPIO1_9  |  |
|  19  | B4.2 | GPIO1_10 |  |
|  22  | B4.3 | GPIO1_11 |  |
|  21  | B4.4 | GPIO1_12 |  |
|  24  | B4.5 | GPIO1_13 |  |
|  23  | B4.6 | GPIO1_14 |  |
|  26  | B4.7 | GPIO1_15 |  |
|//Byte 5//||||
|  25  | B5.0 | GPIO1_16 |  |
|  28  | B5.1 | GPIO1_17 |  |
|  27  | B5.2 | GPIO1_18 |  |
|  84  | B5.3 | GPIO1_19   |    |
|  85  | B5.4 | GPIO1_20   |    |
|  86  | B5.5 | GPIO1_21   |    |
|  87  | B5.6 | GPIO1_22   |    |
|  88  | B5.7 | GPIO1_23   |    |
|//Byte 6//||||
|  91  | B6.0 | GPIO1_24   |    |
|  92  | B6.1 | GPIO1_25   |    |
|  93  | B6.2 | GPIO1_26   |    |
|  94  | B6.3 | GPIO1_27   |    |
|  95  | B6.4 | GPIO1_28   |    |
|  96  | B6.5 | GPIO1_29   |    |
|  97  | B6.6 | GPIO1_30   |    |
|  98  | B6.7 | GPIO1_31   |    |
|//Byte 7//||||
|  99  | B7.0 | GPIO1_32   |    |
|  100 | B7.1 | GPIO1_33   |    |
|  101 | B7.2 | GPIO1_34   |    |
|  102 | B7.3 | GPIO1_35   |    |
|  103 | B7.4 | GPIO1_36   |    |
|  104 | B7.5 | GPIO1_37   |    |
|  105 | B7.6 | GPIO1_38   |    |
|  106 | B7.7 | GPIO1_39   |    |
|//Byte 8//||||
|  107 | B8.0 | GPIO1_40   | TxD0 (transmitted data) of GECKO3xx as RS-232  |
|  108 | B8.1 | GPIO1_41   | RxD0 (received data) of GECKO3xx as RS-232    |
|  109 | B8.2 | GPIO1_42   | DTR0 (data terminal ready) of GECKO3xx as RS-232  |
|  110 | B8.3 | GPIO1_43   | DSR0 (data set ready) of GECKO3xx as RS-232  |
|  111 | B8.4 | GPIO1_44   | RTS0 (request to send) of GECKO3xx as RS-232  |
|  112 | B8.5 | GPIO1_45   | CTS0 (clear to send) of GECKO3xx as RS-232  |
|  113 | B8.6 | GPIO1_46   | DCD0 (carrier detect) of GECKO3xx as RS-232  |
|  114 | B8.7 | GPIO1_47   | RI0 (ring indicator) of GECKO3xx as RS-232  |
|//Byte 9//||||
|  115 | B9.0 | GPIO1_48   | SCK (serial clock) of GECKO3xx as SPI-Master   |
|  116 | B9.1 | GPIO1_49   | MOSI (master out slave in) of GECKO3xx as SPI-Master   |
|  117 | B9.2 | GPIO1_50   | MISO (master in slave out) of GECKO3xx as SPI-Master   |
|  118 | B9.3 | GPIO1_51   | CS1 of GECKO3xx as SPI-Master    |
|  77  | B9.4 | LineSensorIn1   | CS2 of GECKO3xx as SPI-Master |
|  78  | B9.5 | LineSensorOut1  | CS3 of GECKO3xx as SPI-Master |
|  79  | B9.6 | LineSensorIn2   | CD of GECKO3doking for SD-Card |
|  80  | B9.7 | LineSensorOut2  | WD of GECKO3doking for SD-Card |

==== Power ====

^  Pin ^ Name    ^ Description           ^
|  1   | GND     | System GND            |
|  2   | GND     | System GND            |
|  5   | GND     | System GND            |
|  8   | GND     | System GND            |
|  9   | GND     | System GND            |
|  12  | GND     | System GND            |
|  29  | GND     | System GND            |
|  30  | GND     | System GND            |
|  33  | GND     | System GND            |
|  34  | GND     | System GND            |
|  41  | GND     | System GND            |
|  42  | GND     | System GND            |
|  43  | GND     | System GND            |
|  44  | GND     | System GND            |
|  45  | GND     | System GND            |
|  46  | GND     | System GND            |
|  53  | GND     | System GND            |
|  54  | GND     | System GND            |
|  55  | GND     | System GND            |
|  56  | GND     | System GND            |
|  59  | GND     | System GND            |
|  60  | GND     | System GND            |
|  89  | GND     | System GND            |
|  90  | GND     | System GND            |
|  119 | GND     | System GND            |
|  120 | GND     | System GND            |
|  31  | VBUS    | USB supply voltage, provided if one of the modules is connected to an USB port. Can for example be used to charge batteries. According to the USB specification the voltage is in the range of 4.3 to 5.5 V. To avoid that a high equalising current flows between two modules (where each is connected to a USB port) connect a diode between the USB port and the VBUS signal.       |
|  32  | VBUS    | USB supply voltage                        |
|  35  | VBAT    | System battery voltage. In the voltage range of one LiPo Cell (3.7 - 4.5 V). If the board is powered from a different voltage source (such as a LiPo battery with multiple cells in series) the VBAT line must be powered by a voltage regulator with at least 3.3 V. One simple solution is to shorten VBAT with the +3V3 line.       |
|  36  | VBAT    | System battery voltage, 3.3 - 4.5 V           |
|  37  | VBAT    | System battery voltage, 3.3 - 4.5 V           |
|  38  | VBAT    | System battery voltage, 3.3 - 4.5 V           |
|  39  | VBAT    | System battery voltage, 3.3 - 4.5 V           |
|  40  | VBAT    | System battery voltage, 3.3 - 4.5 V           |
|  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   |


==== Singnals - not part of the logical bus ====
^  Pin ^ Name    ^ Description           ^
|//Clock signals//|||
|  7   | EXTCLK0   | Clock line 0, for external or stack internal clock signal distribution. Around the clock lines ground pins are placed to get a pseudo coaxial behavior of the line.  |
|  10  | EXTCLK1 | Clock line 1, for external or stack internal clock signal distribution. Around the clock lines ground pins are placed to get a pseudo coaxial behavior of the line.  |
|//Line sensor signal//|||
|  82  | LineSensorClk   | Clock output signal to trigger the D flip-flop of the line sensors |
|//Reset signal//|||
|  3   | nRESET  | Global reset pin. If low all modules connected to the bus will be reseted. The reset can be done by the USB controller, the FPGA on GECKO3main, by hand or by one of the additional modules connected to the bus. To avoid destroying your reset circuit make sure only one pull-up resistor is mounted on only one board when stacking those together. Additionally make sure ICs as FPGAs and FX2 are only using three-state outputs connected together with the reset circuit. If you do not follow this approach you will risk destroying the reset circuit.|
|//Status signals//|||
|  57  | LOW_BATTERY | Low battery indicating line. This line is pulled high from the power supply module if the battery will get empty   |
|  58  | POWER_GOOD  | POK line. This signal is normal high and is pulled low if the power supply is overloaded or faulty |
|//Communication (I<sup>2</sup>C)//|||
|  81  | SDA     | I<sup>2</sup>C Bus data line, normaly all I<sup>2</sup>C components on the GECKO3 modules are connected to one bus. Place 2.2 kOhm Pull-Up resistors on controller boards |
|  83  | SCL     | I<sup>2</sup>C Bus clock line |


===== IO-BUS 2 pins =====

==== Logical blocks ====

^ Pin ^ Block ^ Signal Name ^ Description ^
|//Byte 10//||||
| 3   | B10.0 | GPIO2_0   | |
| 4   | B10.1 | GPIO2_1   | |
| 5   | B10.2 | GPIO2_2   | |
| 6   | B10.3 | GPIO2_3   | |
| 7   | B10.4 | GPIO2_4   | |
| 8   | B10.5 | GPIO2_5   | |
| 9   | B10.6 | GPIO2_6   | |
| 10  | B10.7 | GPIO2_7   | |
|//Byte 11//||||
| 11  | B11.0 | GPIO2_8   | |
| 12  | B11.1 | GPIO2_9   | |
| 13  | B11.2 | GPIO2_10  | |
| 14  | B11.3 | GPIO2_11  | |
| 15  | B11.4 | GPIO2_12  | |
| 16  | B11.5 | GPIO2_13  | |
| 17  | B11.6 | GPIO2_14  | |
| 18  | B11.7 | GPIO2_15  | |
|//Byte 12//||||
| 19  | B12.0 | GPIO2_16  | |
| 20  | B12.1 | GPIO2_17  | |
| 21  | B12.2 | GPIO2_18  | |
| 22  | B12.3 | GPIO2_19  | |
| 23  | B12.4 | GPIO2_20  | |
| 24  | B12.5 | GPIO2_21  | |
| 25  | B12.6 | GPIO2_22  | |
| 26  | B12.7 | GPIO2_23  | |
|//Byte 13//||||
| 27  | B13.0 | GPIO2_24  | |
| 28  | B13.1 | GPIO2_25  | |
| 29  | B13.2 | GPIO2_26  | |
| 30  | B13.3 | GPIO2_27  | |
| 31  | B13.4 | GPIO2_28  | |
| 32  | B13.5 | GPIO2_29  | |
| 33  | B13.6 | GPIO2_30  | |
| 34  | B13.7 | GPIO2_31  | |
|//Byte 14//||||
| 35  | B14.0 | GPIO2_32  | |
| 36  | B14.1 | GPIO2_33  | |
| 37  | B14.2 | GPIO2_34  | |
| 38  | B14.3 | GPIO2_35  | |
| 39  | B14.4 | GPIO2_36  | |
| 40  | B14.5 | GPIO2_37  | |
| 41  | B14.6 | GPIO2_38  | |
| 42  | B14.7 | GPIO2_39  | |
|//Byte 15//||||
| 43  | B15.0 | GPIO2_40  | |
| 44  | B15.1 | GPIO2_41  | |
| 45  | B15.2 | GPIO2_42  | |
| 46  | B15.3 | GPIO2_43  | |
| 47  | B15.4 | GPIO2_44  | |
| 48  | B15.5 | GPIO2_45  | |
| 49  | B15.6 | GPIO2_46  | |
| 50  | B15.7 | GPIO2_47  | |
|//Byte 16//||||
| 51  | B16.0 | GPIO2_48  | |
| 52  | B16.1 | GPIO2_49  | |
| 53  | B16.2 | GPIO2_50  | |
| 54  | B16.3 | GPIO2_51  | |
| 55  | B16.4 | GPIO2_52  | |
| 56  | B16.5 | GPIO2_53  | |
| 57  | B16.6 | GPIO2_54  | |
| 58  | B16.7 | GPIO2_55  | |
|//Byte 17//||||
| 59  | B17.0 | GPIO2_56  | |
| 60  | B17.1 | GPIO2_57  | |
| 61  | B17.2 | GPIO2_58  | |
| 62  | B17.3 | GPIO2_59  | |
| 63  | B17.4 | GPIO2_60  | |
| 64  | B17.5 | GPIO2_61  | |
| 65  | B17.6 | GPIO2_62  | |
| 66  | B17.7 | GPIO2_63  | |
|//Byte 18//||||
| 67  | B18.0 | GPIO2_64  | |
| 68  | B18.1 | GPIO2_65  | |
| 69  | B18.2 | GPIO2_66  | |
| 70  | B18.3 | GPIO2_67  | |
| 71  | B18.4 | GPIO2_68  | |
| 72  | B18.5 | GPIO2_69  | |
| 73  | B18.6 | GPIO2_70  | |
| 74  | B18.7 | GPIO2_71  | |
|//Byte 19//||||
| 75  | B19.0 | GPIO2_72  | |
| 76  | B19.1 | GPIO2_73  | |
| 77  | B19.2 | GPIO2_74  | |
| 78  | B19.3 | GPIO2_75  | |
| 79  | B19.4 | GPIO2_76  | |
| 80  | B19.5 | GPIO2_77  | |
| 81  | B19.6 | GPIO2_78  | |
| 82  | B19.7 | GPIO2_79  | |
|//Byte 20//||||
| 83  | B20.0 | GPIO2_80  | |
| 84  | B20.1 | GPIO2_81  | |
| 85  | B20.2 | GPIO2_82  | |
| 86  | B20.3 | GPIO2_83  | |
| 87  | B20.4 | GPIO2_84  | |
| 88  | B20.5 | GPIO2_85  | |
| 89  | B20.6 | GPIO2_86  | |
| 90  | B20.7 | GPIO2_87  | |
|//Byte 21//||||
| 91  | B21.0 | GPIO2_88  | |
| 92  | B21.1 | GPIO2_89  | |
| 93  | B21.2 | GPIO2_90  | |
| 94  | B21.3 | GPIO2_91  | |
| 95  | B21.4 | GPIO2_92  | |
| 96  | B21.5 | GPIO2_93  | |
| 97  | B21.6 | GPIO2_94  | |
| 98  | B21.7 | GPIO2_95  | |
|//Byte 22//||||
| 99  | B22.0 | GPIO2_96  | |
| 100 | B22.1 | GPIO2_97  | |
| 101 | B22.2 | GPIO2_98  | |
| 102 | B22.3 | GPIO2_99  | |
| 103 | B22.4 | GPIO2_100 | |
| 104 | B22.5 | GPIO2_101 | |
| 105 | B22.6 | GPIO2_102 | |
| 106 | B22.7 | GPIO2_103 | |
|//Byte 23//||||
| 107 | B23.0 | GPIO2_104 | |
| 108 | B23.1 | GPIO2_105 | |
| 109 | B23.2 | GPIO2_106 | |
| 110 | B23.3 | GPIO2_107 | |
| 111 | B23.4 | GPIO2_108 | |
| 112 | B23.5 | GPIO2_109 | |
| 113 | B23.6 | GPIO2_110 | |
| 114 | B23.7 | GPIO2_111 | |
|//Byte 24//||||
| 115 | B24.0 | GPIO2_112 | |
| 116 | B24.1 | GPIO2_113 | |
| 117 | B24.2 | GPIO2_114 | |
| 118 | B24.3 | GPIO2_115 | |


==== Power ====


^ Pin ^ Signal Name ^ Description ^
| 1   | GND  | System GND|
| 2   | GND  | System GND|
| 119 | GND  | System GND|
| 120 | GND  | System GND|