View source for KAmod I2C-Mini Out 8

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===== Description =====
<b>KAmod I2C-Mini Out8 - Expander 8 low-power outputs controlled by I2C with MCP23008</b><br> <br>
The KAmod I2C-Mini Out8 module contains 8 outputs with low-power N-MOSFET transistors, with a maximum output current of 1 A and a maximum voltage of 50 V. Thanks to the use of the MCP23008 system, control is via the I2C bus.
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[[File:KAmodI2CminiOut8 1.jpg|none|900px|thumb|center]]
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===== Basic features and parameters =====
* 8 outputs, which in the active state provide ground (GND) of the connected power supply
* Outputs with a maximum output current of 1 A and a maximum voltage of 50 V
* Outputs equipped with protective diodes - allow powering small inductive loads, such as relays, solenoid valves, electric motors
* Contains an expander type MCP23008
* Control via I2C interface with a clock speed of max. 1 MHz
* 3 address lines allow connecting 8 modules to one I2C bus
* Power supply of the control part: 3...5 V; power supply of outputs: 3...50 V
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===== Standard Equipment =====
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{| class="wikitable" style="width: 800px;"
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! style="text-align: center;"|Code
! style="text-align: center;"|Description
|-
| style="text-align: center;"|<b>KAmod I2C-Mini Out8</b>
| style="text-align: left;"|
* Assembled and started module
* 1 x straight goldpin header 12-pin raster 2.54 mm
* 1 x straight goldpin header 8-pin raster 2.54 mm

|}
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[[File:KAmodI2CminiOut8 3.jpg|none|900px|thumb|center]]
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===== Schematic =====
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[[File:KAmod_I2C-Mini_Out_8_sch.jpg|none|900px|thumb|center]]
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===== Output Layout =====
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{| class="wikitable" style="width: 1000px;"
|-
! style="text-align: center;"|<b>Designation</b>
! style="text-align: center;"|<b>Function</b>
|-
| style="text-align: center;"|<b>J2, 0...8</b>
| style="text-align: left;"|
*8 outputs with active low state (power supply ground, GND)
|-
| style="text-align: center;"|<b>J2, VCC</b>
| style="text-align: left;"|
*power supply input of output circuits, positive pole
|-
| style="text-align: center;"|<b>J2, G</b>
| style="text-align: left;"|
*output circuit power supply input, negative pole (GND)
|-
|}
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The module outputs are led out as solder points with holes, arranged with a standard 2.54 mm pitch, right at the edge of the board. They allow for soldering wires or goldpins. The pin assignment is shown in the figure below.
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Each output is built from an N-MOSFET transistor and a protective diode. The active output supplies the power supply ground (G - GND), the inactive output is in a high impedance state (HiZ). The maximum output current cannot exceed 1 A, and the maximum output voltage cannot exceed 50 V. Thanks to the use of a protective diode, the outputs can directly control inductive loads, e.g. relays, solenoid valves, electric motors, if their parameters do not exceed the maximum current or voltage.
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The output circuit should be connected to the power supply of the components connected to the outputs - VCC - positive pole, G - negative pole.
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[[File:KAmod_I2C-Mini_Out_8_out.jpg|none|600px|thumb|center]]
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===== Control signals =====
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{| class="wikitable" style="width: 1000px;"
|-
! style="text-align: center;"|<b>Designation</b>
! style="text-align: center;"|<b>Function</b>
|-
| style="text-align: left;"|<b>SD (J1)</b>
| style="text-align: left;"| SDA (data) signal of the I2C interface
|-
| style="text-align: left;"|<b>SC (J1)</b>
| style="text-align: left;"| SCL (clock) signal of the I2C interface
|-
| style="text-align: left;"|<b>RST (J1)</b>
| style="text-align: left;"| Input that resets the system
|-
| style="text-align: left;"|<b>A0, A1, A2 (J1)</b>
| style="text-align: left;"| Inputs that allow you to set the I2C interface address (bits 2, 1, 0). By default, set to logical 0.
|}
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The KAmod I2C-Mini Out8 module is controlled via the I2C interface, which can be clocked with a 100 kHz, 400 kHz or 1 MHz clock signal. The functions of the pins on the J1 connector are as follows:
* The I2C control interface signals are SD – SDA, and SC – SCL. They are not equipped with pull-up resistors – the control system must contain the appropriate elements.
* Inputs A0, A1, A2 allow you to set the address (bits no. 2, 1 and 0) that the module connected to the I2C interface will have. By default, these inputs are connected to ground via resistors (pull-down) and assume logical 0 values. Connecting the positive power supply to inputs A0/A1/A2 sets logical 1 for the lowest address bits.

* All available I2C interface addresses are in the range 0x20...0x27.
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Detailed information on communication and configuration of the MCP23008 is available in the technical documentation of this system.
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Additional signals are:
* The reset signal (RST) is used to reset the MCP23008 on the KAmod I2C-Mini Out8 board, which restores all settings to their initial state.

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[[File:KAmod_I2C-Mini_Out_8_syg.jpg|none|600px|thumb|center]]
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===== Power =====
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{| class="wikitable" style="width: 1000px;"
|-
! style="text-align: center;"|<b>Designation</b>
! style="text-align: center;"|<b>Function</b>
|-
| style="text-align: left;"|
*<b>V+ (J1)</b><br>
*<b>GND (J1)</b>
| style="text-align: left;"|
*control circuit power supply input, positive pole<br>
*control circuit power supply input, negative pole (GND)
|-
| style="text-align: left;"|
*<b>VCC (J2)</b><br>
*<b>G (J2)</b>
| style="text-align: left;"|
*power input for output circuits, positive pole<br>
*power input for output circuits, negative pole (GND)
|-
|}
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The control circuit of the KAmod I2C-Mini Out8 module can be powered by a DC voltage of 3...5 V, connected to the V+ and GND pins on the J1 connector.
<br><br>
The output circuit of the KAmod I2C-Mini Out8 module can be powered by a DC voltage of 3...50 V, connected to the VCC and G pins on the J2 connector.
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[[File:KAmod_I2C-Mini_Out_8_pwr.jpg|none|600px|thumb|center]]
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===== Dimensions =====
The dimensions of the KAmod I2C-Mini Out8 board are 31x23.5 mm. There are 2 mounting holes on the board with a diameter of 3.2 mm.
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[[File:KAmod_I2C-Mini_Out_8_wym.jpg|none|650px|thumb|center]]
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===== Test program =====
The test program was written in the Arduino environment for the KAmodESP32 POW RS485 board. The KAmod I2C-Mini Out8 module was connected via the I2C interface.
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<syntaxhighlight lang="arduino" line>
#include <Wire.h>
//#include <Adafruit_MCP23X17.h>
#include <Adafruit_MCP23X08.h>

//LED
#define LED_PIN         2 
#define MY_DELAY        2000
#define TEST_LED_ON     1
#define TEST_LED_OFF    0

//I2C
#define I2C_SDA         33
#define I2C_SCL         32
#define I2C_FREQ        100000
#define MCP23008_ARD    0x20

TwoWire I2Cbus = TwoWire(0);
Adafruit_MCP23X08 MCPIO;
int i;

//-----------------------------------------------------------------
void setup() {
  Serial.begin(115200);
  Serial.println();
  Serial.println("Hello. KAmod I2C Mini Out 8 test");

  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, HIGH);

  delay(500);
  while(!I2Cbus.begin(I2C_SDA, I2C_SCL, I2C_FREQ)){
    Serial.println("I2C init failed...");
    delay(500);
  }
  while (!MCPIO.begin_I2C(MCP23008_ARD, &I2Cbus)) {
    Serial.println("MCP init failed...");
    delay(500);
  }

  Serial.println("I2C init OK");
  delay(100);
}

//-----------------------------------------------------------------
void loop() {
  if (i & 1){
    digitalWrite(LED_PIN, TEST_LED_ON);
  } else {
    digitalWrite(LED_PIN, TEST_LED_OFF);
  }
  
  Serial.print("Out: ");
  Serial.println(i);

  MCPIO.pinMode(i, OUTPUT);
  MCPIO.digitalWrite(i, TEST_LED_ON);
  delay(100);
  MCPIO.pinMode(i, OUTPUT);
  MCPIO.digitalWrite(i, TEST_LED_OFF);
  delay(100);
  
  i++;
  if (i  >= 8){
    i = 0;
  }
}
</syntaxhighlight>
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===== Links =====
*[https://wiki.kamamilabs.com/images/1/12/MCP23008.pdf DatasheetMCP23008]
*[https://github.com/KAMAMI-Labs/KAmod-I2C-Mini-Out8.git Sample programs]
*[https://wiki.kamamilabs.com/images/4/4a/KAmod_I2C_Out8.zip CAD Model (STEP)]