MCP23X17EV Microchip Technology, MCP23X17EV Datasheet - Page 13

• Manufacturer Part Number: MCP23X17EV
• Description: BOARD EVAL FOR MCP23X17
• Manufacturer: Microchip Technology

Specifications of MCP23X17EV

• Main Purpose: Interface, GPIO Expander
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MCP23017, MCP23S17
• Primary Attributes: (2) 16-Bit GPIO Expanders, I2C and SPI
• Secondary Attributes: 4 Momentary Switches, 12 LEDs
• Processor To Be Evaluated: MCP23x17
• Data Bus Width: 16 bit
• Interface Type: SPI
• Silicon Manufacturer: Microchip
• Silicon Core Number: MCP23017, MCP23S17
• Kit Application Type: Interface
• Application Sub Type: GPIO Expander
• Kit Contents: Board
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

2.4
2.5
© 2006 Microchip Technology Inc.
MCP23X17 EVALUATION BOARD DESCRIPTION
FIRMWARE DESCRIPTION
2.4.1
1. MCP23017 and MCP23S17 - The two devices under evaluation/demonstration.
2. LEDs - These are connected to the MCP23X17 GPIO configured as outputs.
3. Momentary Buttons - These are connected to the MCP23X17 configured as
4. PIC16F818 - Reads the selector switch and controls the MCP23X17 devices.
5. Headers - There are two headers which are connected to the MCP23X17 pins to
6. Jumpers - The jumpers are used to isolate the MCP23X17 pins so they can be
7. Power - The boards can be powered by 9V via the power jack (J2) or by applying
See Figure 2-2 for the main firmware flow diagram
1. The firmware first configures the PIC16F818 microcontroller.
2. The firmware configures the MCP23X17 devices (4-inputs, 12-outputs, enable
3. The firmware checks the selector switch to determine which MCP23X17 to
4. The “other” MCP23X17 is configured to all inputs so that it does not cause
5. The MCP23X17 inputs are sampled.
6. The LEDs light up in a pattern as defined by the button which was pressed. If no
Both devices are connected to the same inputs and outputs and selector switch
is used to select which device the PICmicro controls. A mux is used to route the
serial (I
inputs.
allow off-board connections.
connected to an off-board circuit. The jumpers are not populated, however, they
are shorted by a trace on the bottom of the PCB.
5V directly to the power points (TP1 and TP2).
interrupts, etc.).
communicate with during the main loop.
contention on LED connections.
button is pressed, the LEDs maintain the current sequence.
Major Board Components
2
C or SPI) from the PICmicro to the MCP23X17.
DS51592B-page 9