Diff: main.cpp

Revision:

17:54a003ac9610

Parent:

16:fbe18dbc2fb7

Child:

18:452b5da21cfd

--- a/main.cpp	Tue Jul 16 20:47:21 2013 +0000
+++ b/main.cpp	Wed Jul 17 20:47:41 2013 +0000
@@ -1,11 +1,11 @@
-//This main funtion mainly implements a mode transfer.
-//When mcu resets, it's in MODE_IDLE. Then depends on the keyboard input, the 
+//This main funtion implements a mode transfer.
+//When mcu resets, it's in MODE_IDLE. Then depends on the keyboard input(1 to 7), the 
 //mode switches to transition modes such as 
 //MODE_CHAxPHA, which is for phase input of channel x, or
 //MODE_CHAxAMP, which is for attenuation input of channel x, or
 //MODE_DISPLAY, which is for displaying the current parameters, or
 //MODE_HELP, which is for displaying the help infomation, or
-//MODE_SEND, which is for sending the bit stream through the SPI bus.
+//MODE_SEND, which is for sending the bit stream through the SPI bus by MOSI and read the data back from MISO.
 //After each transition mode completes, mcu returns to MODE_IDLE to wait for another user input.
 
 
@@ -15,9 +15,9 @@
 #include "handlers.h"
 //#define DEBUG
 
-Serial pc(USBTX, USBRX);
+Serial pc(USBTX, USBRX);   // serial io
 SPI spi(PTD2, PTD3, PTD1); // mosi, miso, sclk
-DigitalOut cs(PTD0);
+DigitalOut cs(PTD0);       //SPI chip select
 
 char recv;
 char temp;
@@ -41,10 +41,11 @@
 
 int main() {
 
-    pc.baud(19200);  //config buad rate. Note: 115200 seems too high for the current board
-    cs = 1;   //spi config
-    spi.format(8,0);  // 16 bit frame is not working, so need to send twice 8 bit frame
-    spi.frequency(1000000);
+    pc.baud(19200);   //config buad rate. Note: 115200 seems too high for the current board
+    cs = 1;           //spi config
+    spi.format(8,0);  //16 bit frame is not working, so need to send twice 8 bit frame
+                      //For more info about format, see http://mbed.org/forum/bugs-suggestions/topic/4419/?page=1#comment-22056
+    spi.frequency(1000000);  
     
     state = MODE_IDLE;
     line_buf[3] = 0;
@@ -64,7 +65,7 @@
                 pc.printf("%s", main_menu);
                 recv = pc.getc();
                 mode_idle_handler(&state, recv);  //change state based on recv input
-                //pc.printf("%d", state);
+                
                 break;
                 
             case MODE_CHA1PHA:
@@ -251,7 +252,7 @@
                 spi_first_byte_s = (cha2_amp << 4) | (cha2_pha);
                 spi_second_byte_s = (cha1_amp << 4) | (cha1_pha);
                 
-                cs = 0;   // start sending, send and recond the response(send and loopback in this case)
+                cs = 0;   //SPI start sending, send and recond the response
                 spi_first_byte_r = spi.write(spi_first_byte_s);
                 spi_second_byte_r = spi.write(spi_second_byte_s);
                 cs = 1;
@@ -281,13 +282,13 @@
                 pc.printf("\n\nParameters sent OK\n\n\n\n");
                 
                 
-                //output the previous parameters:
+                //Output the previous parameters:
                 pc.printf("Now displaying the previous parameters\n");
                 pc.printf("\nPrevious phase shift  for RF out1 is %d degrees\n", (spi_second_byte_r&0x07)*-7);
                 pc.printf("Previous attentuation for RF out1 is %.1f dB\n", (spi_second_byte_r>>4)*5.0/10.0);
                 pc.printf("Previous phase shift  for RF out2 is %d degrees\n", (spi_first_byte_r&0x07)*-7);
                 pc.printf("Previous attentuation for RF out2 is %.1f dB\n", (spi_first_byte_r>>4)*5.0/10.0);
-                //spi bit stream for previous parameters
+                //SPI bit stream for previous parameters
                 pc.printf("\nSPI bit stream received:\n");
                 pc.printf("%s", bit_index);
                 for(i=0; i<=7; i++)