Romilly Cocking / Mbed 2 deprecated MCP23S17Test

Library test v 0.4

Dependencies:   mbed MCP23S17

main.cpp@4:15297eea34f6, 2010-08-28 (annotated)

Committer:
romilly
Date:
Sat Aug 28 09:51:44 2010 +0000
Revision:
4:15297eea34f6
Parent:
3:8f437a811ecf 

        

        
Who changed what in which revision?

        

            
                
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/* Test drive the MCP23S17 library





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* Copyright (c) 2010 Romilly Cocking





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* Released under the MIT License: http://mbed.org/license/mit





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*





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* See http://mbed.org/users/romilly/notebook/mcp23s17-addressable-16-bit-io-expander-with-spi/





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*





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* NB this code is intended to test the driver library, not the chip





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* which is assumed to work as specified





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* MCP23S17 datasheet http://ww1.microchip.com/downloads/en/DeviceDoc/21952b.pdf





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* version 0.4





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*/





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#include "mbed.h"





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#include "MCP23S17.h"





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SPI spi(p5, p6, p7);





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// A0, A1, A2 of the MCP23S17  are tied to ground on the breadboard, so the 8-bit address for writes is 0x40





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// This is referred to as the opcode in the device datasheet





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char writeOpcode = 0x40;





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// mbed pin20 is connected to ~chipSelect of the MCP23S17





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MCP23S17 chip = MCP23S17(spi, p20, writeOpcode); // create MCP23S17





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DigitalOut    chipNotReset(p14); // connected to ~reset of the MCP23S17





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DigitalInOut chipA0(p12);  // connected to Port A bit 0 of the MCP23S17





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DigitalInOut chipA1(p30);     // connected to Port A bit 1 via 100k resistor





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DigitalInOut  chipB0(p10); // connected to Port B bit 0 of the MCP23S17





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DigitalIn   chipIntA(p16); // connected to INTA on the MCP23S17





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DigitalIn   chipIntB(p18); // connected to INTB on the MCP23S17





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void reset() {





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    // I'm not sure we need the delays, but better safe than sorry.





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    // Ensure mbed bi-directional pins set to input





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    chipA0.input();





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    chipA1.input();





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    chipB0.input();





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    chipNotReset = 0;  // reset chip





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    wait_us(10);





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    chipNotReset = 1;





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    wait_us(10);





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}





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void checkEqual(int expected, int actual, char * description) {





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    if (expected != actual) {





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        printf("%s **TEST FAILED** - expected %i but get %i\r\n", description, expected, actual);





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        exit(-1);





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    }





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}





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void testInputFromPortA() {





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    reset();





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    chipA0.output(); // prepare to output from the mbed





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    chip.direction(PORT_A,0x01); // chip Port A bit 0 set to input





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    chipA0 = 0;





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    checkEqual(0, chip.read(PORT_A) && 0x1,"read from A0");





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    chipA0 = 1;





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    checkEqual(1, chip.read(PORT_A) && 0x1,"read from A0");





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}





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void testInputFromPortB() {





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    reset();





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    chipB0.output(); // output from the mbed





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    chip.direction(PORT_B,0x01); //  bit 0 set to input





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    chipB0 = 0;





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    checkEqual(0, chip.read(PORT_B) && 0x1,"read from B0");





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    chipB0 = 1;





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    checkEqual(1, chip.read(PORT_B) && 0x1,"read from B0");





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}





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void testOutputToPortA() {





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    reset();





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    chipA0.input(); // input to the mbed





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    chip.direction(PORT_A, 0xFE); //  bit 0 set to output





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    chip.write(PORT_A,0x00);





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    checkEqual(0, int(chipA0),"write to A0");





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    chip.write(PORT_A,0x01);





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    checkEqual(1, int(chipA0),"write to A0");





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}





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void testOutputToPortB() {





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    reset();





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    chipB0.input(); // input to the mbed





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    chip.direction(PORT_B, 0xFE); //  bit 0 set to output





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    chip.write(PORT_B,0x00);





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    checkEqual(0, int(chipB0),"write to B0");





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    chip.write(PORT_B,0x01);





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    checkEqual(1, int(chipB0),"write to B0");





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}





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void testInterruptEnableOnPortA() {





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// NB by default both int pins are Active-LOW





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    reset();





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    chipA0.output(); // output from the mbed





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    chip.direction(PORT_A, 0x01); //  bit 0 set to input





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    chipA0 = 1;





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    checkEqual(1, int(chipIntA),"interrupts not yet enabled");





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    chipA0 = 0;





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    chip.interruptEnable(PORT_A, 0x01); // interupt enabled on pin A0





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    checkEqual(1, int(chipIntA), "value has not changed");





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    chipA0 = 1;





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    wait_us(1); // test fails without this - mbed is too darned fast!





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    checkEqual(0, int(chipIntA), "value has changed");





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}





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void testInterruptEnableOnPortB() {





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// NB by default both int pins are Active-LOW





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    reset();





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    chipB0.output(); // output from the mbed





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    chip.direction(PORT_B, 0x01); //  bit 0 set to input





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    chipB0 = 1;





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    chip.interruptEnable(PORT_B, 0x01); // interupt enabled on pin 0





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    wait_us(1);





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    checkEqual(0, int(chipIntB), "interruptB");





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}





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void testMirrorInterrupts() {





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    reset();





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    chipB0.output(); // output from the mbed





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    chip.direction(PORT_B, 0x01); //  bit 0 set to input





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    chipB0 = 1;





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    chip.interruptEnable(PORT_B, 0x01); // interupt enabled on pin 0





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    wait_us(1);





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    checkEqual(0, int(chipIntB), "interruptB");





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    checkEqual(1, int(chipIntA), "before mirroring"); // no interrupt A yet





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    chip.mirrorInterrupts(true);





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    wait_us(1);





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    checkEqual(0, int(chipIntA), "after mirroring");





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    chip.mirrorInterrupts(false);





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    wait_us(1);





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    checkEqual(1, int(chipIntA), "after mirroring turned off");





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}





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void testInterruptPolarity() {





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// NB by default both int pins are Active-LOW





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// interrupt off (so HIGH) after POR





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    reset();





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    checkEqual(1, int(chipIntA),"interrupt ACTIVE_LOW by default");





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    chip.interruptPolarity(ACTIVE_HIGH);





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    wait_us(1);





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    checkEqual(0, int(chipIntA), "interrupt ACTIVE_HIGH");





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    chip.interruptPolarity(ACTIVE_LOW);





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    wait_us(1);





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    checkEqual(1, int(chipIntA), "interrupt ACTIVE_LOW");





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}





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void testInterruptControlAndDefaultValueOnPortA() {





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    reset();





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    chipA0.output(); // output from the mbed





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    chip.direction(PORT_A, 0x01); //  bit 0 set to input





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    chipA0 = 0;





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    checkEqual(1, int(chipIntA),"interrupt ACTIVE_LOW by default");





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    chip.interruptEnable(PORT_A, 0x01); // interupt enabled on pin 0





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    chip.defaultValue(PORT_A, 0x01); // default value != input value





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    checkEqual(1, int(chipIntA),"still no interrupt"); // interrupt control still set to interrupt on change





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    chip.interruptControl(PORT_A, 0x01);





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    wait_us(1);





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    checkEqual(0, int(chipIntA), "expecting interrupt as default != input");





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}





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void testConfigurePullUpsOnPortA() {





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    reset();





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    chipA1.output();





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    checkEqual(0, chip.read(PORT_A), "without pull-up input should be 0");





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    chip.configurePullUps(PORT_A, 0x02); // pin A1 pull-up enabled





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    checkEqual(2, chip.read(PORT_A), "pull-up should raise chip input to 1");





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}





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int main() {





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    testInputFromPortA();





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    testInputFromPortB();





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    testOutputToPortA();





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    testOutputToPortB();





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    testInterruptEnableOnPortA();





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    testInterruptEnableOnPortB();





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    testInterruptPolarity();





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    testMirrorInterrupts();





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    testInterruptControlAndDefaultValueOnPortA();





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    testConfigurePullUpsOnPortA();





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    // testInterruptControlAndDefaultValueOnPortB();





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    // testInterruptCaptureA();





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    // testInterruptCaptureB();





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    printf("all tests OK\r\n");





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}