Leonardo Leonardo / Mbed 2 deprecated TestSPI

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Dependencies:   mbed

main.cpp@0:b191e77dc856, 2012-02-27 (annotated)

Committer:
polytech01
Date:
Mon Feb 27 16:30:10 2012 +0000
Revision:
0:b191e77dc856
Test SPI - Leonardo Wesseling

Who changed what in which revision?

UserRevisionLine numberNew contents of line
polytech01 0:b191e77dc856 1 #include "mbed.h"
polytech01 0:b191e77dc856 2
polytech01 0:b191e77dc856 3
polytech01 0:b191e77dc856 4 SPI spi(p11, p12, p13); // mosi, miso, sclk
polytech01 0:b191e77dc856 5 DigitalOut cs(p14);
polytech01 0:b191e77dc856 6
polytech01 0:b191e77dc856 7 Serial pc(USBTX, USBRX); // tx, rx
polytech01 0:b191e77dc856 8
polytech01 0:b191e77dc856 9 // Not possible to use inline assembler language with this device, error 1044
polytech01 0:b191e77dc856 10 /*#pragma arm
polytech01 0:b191e77dc856 11 void NOP()
polytech01 0:b191e77dc856 12 {
polytech01 0:b191e77dc856 13
polytech01 0:b191e77dc856 14 __asm
polytech01 0:b191e77dc856 15 {
polytech01 0:b191e77dc856 16 NOP
polytech01 0:b191e77dc856 17 }
polytech01 0:b191e77dc856 18 }
polytech01 0:b191e77dc856 19 #pragma thumb*/
polytech01 0:b191e77dc856 20
polytech01 0:b191e77dc856 21
polytech01 0:b191e77dc856 22
polytech01 0:b191e77dc856 23
polytech01 0:b191e77dc856 24
polytech01 0:b191e77dc856 25 int main() {
polytech01 0:b191e77dc856 26 // Setup the spi for 8 bit data, high steady state clock,
polytech01 0:b191e77dc856 27 // second edge capture, with a 1MHz clock rate
polytech01 0:b191e77dc856 28 spi.format(8,0);
polytech01 0:b191e77dc856 29 spi.frequency(1000000);
polytech01 0:b191e77dc856 30 int teste, result, b=0;
polytech01 0:b191e77dc856 31
polytech01 0:b191e77dc856 32
polytech01 0:b191e77dc856 33 teste=0xAA;
polytech01 0:b191e77dc856 34
polytech01 0:b191e77dc856 35 cs=0;
polytech01 0:b191e77dc856 36 pc.printf("Answer before = %d\n\r", teste);
polytech01 0:b191e77dc856 37
polytech01 0:b191e77dc856 38
polytech01 0:b191e77dc856 39 spi.write(teste);
polytech01 0:b191e77dc856 40
polytech01 0:b191e77dc856 41 cs=1; // it's necessary to close and open the connection for the program to work, we believe that's necessary to exchange the buffer values
polytech01 0:b191e77dc856 42 // not exactly sure how much must this delay be
polytech01 0:b191e77dc856 43
polytech01 0:b191e77dc856 44 if(b<1){} // delay necessary between closing and opening a connection with the slave, we believe it's because of the high clock value of the mbed
polytech01 0:b191e77dc856 45
polytech01 0:b191e77dc856 46
polytech01 0:b191e77dc856 47
polytech01 0:b191e77dc856 48 cs=0;
polytech01 0:b191e77dc856 49 result=spi.write(0x00); // to read the value of the previous reply from the slave, it's necessary to make another write sending a dummy byte
polytech01 0:b191e77dc856 50 cs=1;
polytech01 0:b191e77dc856 51
polytech01 0:b191e77dc856 52
polytech01 0:b191e77dc856 53 pc.printf("Answer later= 0x%X\n\r", result);
polytech01 0:b191e77dc856 54 // Maybe what is happening is that we need a bigger delay between the two writes so that it works the first time,maybe result is showing not the
polytech01 0:b191e77dc856 55 //value of the previous write in this run of the program, but the value stored in the buffer in the previous run
polytech01 0:b191e77dc856 56
polytech01 0:b191e77dc856 57
polytech01 0:b191e77dc856 58
polytech01 0:b191e77dc856 59
polytech01 0:b191e77dc856 60 }