Diff: main.cpp

Revision:

0:52f83e5addd7

Child:

1:d154278f2ca1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Dec 05 10:33:22 2017 +0000
@@ -0,0 +1,107 @@
+#include "mbed.h"
+/*
+    AUTHOR  Mariwan Jalal
+   These projects try to make a communications channel between to NUCELO-L476RG
+   using SPI protocol (Slave-Master). 
+   You can send any kind of object and reproduced between the two module 
+    USE IT AT YOUR OWN RESPONSIBILITY .. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND
+
+*/
+
+/*
+    These projects should be used together
+    SPI_NUCLEO_MASTER
+    SPI_NUCLEO_SLAVE
+*/
+
+/*
+Slave communication is shifted by one byte. To respond for ex for a START byte,
+you need to put the ACK byte prepared on the bus even before having the START
+byte received by the slave. As the Master write the SPI bus the START Command,
+the prepared byte on the slave SPI bus will be transferred to the Master
+immediately. So, you need to prepare the Slave device to shift the bytes by
+one byte  as in the following example.
+*/
+
+
+
+Serial pc(USBTX,USBRX);
+
+
+
+#define SPI_DUMMY     0X00
+#define SPI_CMD       0XADAD     //Anything as a CMD code.
+#define SPI_FAULT     0xDD       //Anything as a part of 16 bit as control byte
+
+#ifdef _DEBUG
+extern Serial pc;
+#define DEBUG_MESSAGE(...) pc.printf(__VA_ARGS__)
+#else
+#define DEBUG_MESSAGE(...)
+#endif
+
+typedef unsigned char byte;
+
+SPISlave slave(SPI_MOSI, SPI_MISO, SPI_SCK ,PA_4);
+int res=0;
+float d,c,e;
+
+/*This will be the float number we wish to transfer. 
+You can make a struct of multiple variable and send it in the same way*/
+
+typedef union SPI_Packet_t{
+float sensor;
+byte SPI_Packet[sizeof(float)];
+};
+
+SPI_Packet_t packet;
+int main()
+{
+    pc.printf("Testing is started from slave side\n");
+    slave.format(16,0);
+    slave.frequency(1000000);
+    unsigned short vs=0;
+    slave.reply(SPI_DUMMY);   // Prime reply
+    unsigned short tempVal=0;
+    packet.sensor=1000.02;    //Value of the float number we wish to communicate
+    while(1) {
+        if(slave.receive()) {
+            tempVal=(unsigned short) slave.read();        //Real command
+            printf("----------------\n%x\n",tempVal);
+            /*
+                The switch is not necessary if you have only one command between
+                 master-slave. This is useful if you wish to send different 
+                 object depending on the command.
+            */
+            switch(tempVal){
+            case SPI_CMD: {    /*Use this if you have different commands 
+                                for sending different objects to the master.*/
+                            tempVal=(sizeof(float))<<8| packet.SPI_Packet[0];
+                            pc.printf("Packet=%x\n",tempVal);
+                            slave.reply(tempVal);
+                            for(unsigned int i=1; i<sizeof(float); i++){
+                                while(!(slave.receive()))
+                                    wait_ms(1);
+                            vs=slave.read();        //Real command
+                            if (vs==SPI_DUMMY){
+                                //Continue sending bytes
+                                {
+                                  tempVal=0x00FF & packet.SPI_Packet[i];
+                                  pc.printf("Packet=%x\n",tempVal);
+                                  slave.reply(tempVal);
+                                }
+                            }
+                            else {
+                                slave.reply(SPI_FAULT); //ERROR CODE
+                                slave.reply(SPI_DUMMY);     //dummy ..skiped value
+                            }
+                        }
+                    }
+
+                    break;
+            }
+
+         }
+
+    }
+}