Boa-Lin Lai / Mbed 2 deprecated MCP23S17_Basic_IO_Demo

ece4180 lab1

Dependencies:   MCP23S17 mbed

Fork of MCP23S17_Basic_IO_Demo by jim hamblen

main.cpp@3:2aa5a8376678, 2016-09-07 (annotated)

Committer:
boalinlai
Date:
Wed Sep 07 15:30:55 2016 +0000
Revision:
3:2aa5a8376678
Parent:
2:934a0500abde
Child:
4:a361b0d3aaaf
lab1 extra credit;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
4180_1 2:934a0500abde 1 // A simple IO demo using the MCP23S17 library
4180_1 2:934a0500abde 2 //
4180_1 2:934a0500abde 3 // MCP23S17 Library Copyright (c) 2010 Romilly Cocking
4180_1 2:934a0500abde 4 // Released under the MIT License: http://mbed.org/license/mit
4180_1 2:934a0500abde 5 //
4180_1 2:934a0500abde 6 // See http://mbed.org/users/romilly/notebook/mcp23s17-addressable-16-bit-io-expander-with-spi/
4180_1 2:934a0500abde 7 //
4180_1 2:934a0500abde 8 //
4180_1 2:934a0500abde 9 // MCP23S17 datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/21952b.pdf
4180_1 2:934a0500abde 10 // uses MCP23S17 library version 0.4
4180_1 0:12f4911d7ba0 11
4180_1 0:12f4911d7ba0 12 #include "mbed.h"
4180_1 0:12f4911d7ba0 13 #include "MCP23S17.h"
4180_1 2:934a0500abde 14 // Create SPI bus
4180_1 0:12f4911d7ba0 15 SPI spi(p5, p6, p7);
4180_1 2:934a0500abde 16 //
4180_1 2:934a0500abde 17 // Wiring Connections:
4180_1 0:12f4911d7ba0 18 // mbed p5,p6,p7 are tied to MCP23S17 SI, SO, SCK pins
4180_1 2:934a0500abde 19 // mbed p20 to MCP23S17 CS
4180_1 2:934a0500abde 20 // MCP23S17 reset pin pulled high
4180_1 2:934a0500abde 21 // MCP23S17 GPA0 connected to GPB0 for loopback test
4180_1 0:12f4911d7ba0 22 // A0, A1, A2 of the MCP23S17 are tied to ground on the breadboard, so the 8-bit address for writes is 0x40
4180_1 0:12f4911d7ba0 23 // This is referred to as the opcode in the device datasheet
4180_1 2:934a0500abde 24 char Opcode = 0x40;
4180_1 0:12f4911d7ba0 25
4180_1 0:12f4911d7ba0 26 // Next create a MCP23S17
4180_1 0:12f4911d7ba0 27 // mbed p20 is connected to ~chipSelect on the MCP23S17
4180_1 2:934a0500abde 28 MCP23S17 chip = MCP23S17(spi, p20, Opcode);
boalinlai 3:2aa5a8376678 29 MCP23S17 chip2 = MCP23S17(spi, p19, Opcode);
4180_1 0:12f4911d7ba0 30
4180_1 2:934a0500abde 31 // Optional software reset - mbed p14 to MCP23S17 reset pin
4180_1 2:934a0500abde 32 // DigitalOut reset(p14);
4180_1 1:70e1ebe47253 33
4180_1 0:12f4911d7ba0 34 DigitalOut led1(LED1); // mbed LED1 is used for test status display
4180_1 0:12f4911d7ba0 35
4180_1 0:12f4911d7ba0 36 int main() {
4180_1 1:70e1ebe47253 37 // The MCP23S17 reset pin can just be pulled high, since it has a power on reset circuit.
4180_1 1:70e1ebe47253 38 // The reset pin can be used for a software forced reset by pulling it low with an mbed GPIO pin.
4180_1 1:70e1ebe47253 39 // But just leave it pulled high for this simple demo code.
4180_1 0:12f4911d7ba0 40 // After a power on reset, both IO ports default to input mode
4180_1 0:12f4911d7ba0 41 //
4180_1 1:70e1ebe47253 42 // Here is the optional code for a software reset
4180_1 1:70e1ebe47253 43 // reset = 0;
4180_1 1:70e1ebe47253 44 // wait_us(1);
4180_1 1:70e1ebe47253 45 // reset = 1;
4180_1 1:70e1ebe47253 46 //
4180_1 0:12f4911d7ba0 47 // Set all 8 Port A bits to output direction
boalinlai 3:2aa5a8376678 48 chip.direction(PORT_A, 0xFF);
4180_1 0:12f4911d7ba0 49 // Set all 8 Port B bits to input direction
boalinlai 3:2aa5a8376678 50 chip.direction(PORT_B, 0x00);
boalinlai 3:2aa5a8376678 51
boalinlai 3:2aa5a8376678 52 // second chip
boalinlai 3:2aa5a8376678 53 chip2.direction(PORT_A, 0x00);
boalinlai 3:2aa5a8376678 54 // Set all 8 Port B bits to input direction
boalinlai 3:2aa5a8376678 55 chip2.direction(PORT_B, 0xFF);
boalinlai 3:2aa5a8376678 56
boalinlai 3:2aa5a8376678 57
4180_1 0:12f4911d7ba0 58 led1=0;
4180_1 0:12f4911d7ba0 59 // Start Loopback test sending out and reading back values
4180_1 0:12f4911d7ba0 60 // loopback test uses A0 and B0 pins - so use a wire to jumper those two pins on MCP23S17 together
4180_1 0:12f4911d7ba0 61 while (1) {
4180_1 0:12f4911d7ba0 62 // write 0xAA to MCP23S17 Port A
boalinlai 3:2aa5a8376678 63 //if( < 0.1)
boalinlai 3:2aa5a8376678 64 //{
boalinlai 3:2aa5a8376678 65 chip.write(PORT_B, 0x01 & (chip2.read(PORT_B) &0x01));
boalinlai 3:2aa5a8376678 66 //wait(0.05);
boalinlai 3:2aa5a8376678 67 //}
boalinlai 3:2aa5a8376678 68 /*else
boalinlai 3:2aa5a8376678 69 {
4180_1 0:12f4911d7ba0 70 // read back value from MCP23S17 Port B and display B0 on mbed led1
boalinlai 3:2aa5a8376678 71 //led1 = chip.read(PORT_B)& 0x01;
4180_1 0:12f4911d7ba0 72 // write 0x55 to MCP23S17 Port A
boalinlai 3:2aa5a8376678 73 chip.write(PORT_B, 0x1);
boalinlai 3:2aa5a8376678 74 }*/
boalinlai 3:2aa5a8376678 75
boalinlai 3:2aa5a8376678 76 led1 = chip.read(PORT_A)& 0x01;
4180_1 0:12f4911d7ba0 77 // read back value from MCP23S17 Port B and display B0 on mbed led1
boalinlai 3:2aa5a8376678 78 //led1 = chip.read(PORT_B)& 0x01;
boalinlai 3:2aa5a8376678 79 wait(0.05);
4180_1 2:934a0500abde 80 // led1 should blink slowly when it is all working
4180_1 0:12f4911d7ba0 81 }
4180_1 0:12f4911d7ba0 82 }