main.cpp

00001 #include "mbed.h"
00002 
00003 //#include <stdarg.h>
00004 #include <stdio.h>
00005 #include <stdlib.h>
00006 #include <string.h>
00007 
00008 /*
00009 Instructions for use: connect the mbed to a parallel port using these connexions.
00010 use a terminal program to connect via USB to the mbed side. */
00011 
00012 /* This is for testing since it uses the serial port at 9600 bauds to connect to a PC */
00013 
00014 /*
00015   8255          Parallel    Pin     Bit
00016   PC7   /OBF    ->  /ACK        10      6
00017   PC6   /ACK    <-  /SLCTIN     17      3
00018   PC5   IBF     ->  BUSY        11      7
00019   PC4   /STB    <-  /STB        1       0
00020 
00021 15 nError       -> p9       not used
00022 13 Select       -> p10      not used
00023 12 PE           -> p11      not used
00024 11 Busy         -> p12      MISO
00025 10 nAck         -> p13      not used
00026 
00027  1 nStrobe      -> p14      MOSI
00028 14 nAutoFeed    -> p15      SCLK
00029 16 nInit        -> p16      not used
00030 17 nSelectIn    -> p17      not used
00031 */
00032 
00033 DigitalOut MISO(p12);
00034 DigitalIn MOSI(p14);
00035 InterruptIn SCLK(p15);
00036 
00037 /*
00038 CE0 p30  p0.4
00039 CE1 p29  p0.5
00040 CE2 p8   p0.6
00041 CE3 p7   p0.7
00042 CE4 p6   p0.8
00043 CE5 p5   p0.9
00044 CE6 p28  p0.10
00045 CE7 p27  p0.11
00046 */
00047 BusInOut PtrData(p30,p29,p8,p7,p6,p5,p28,p27);
00048 
00049 #define __DOUTBUFSIZE 256
00050 #define __DINBUFSIZE 256
00051 char __outstr[__DOUTBUFSIZE];
00052 char __instr[__DINBUFSIZE];
00053 
00054 Serial pc(USBTX, USBRX); // tx, rx
00055 
00056 unsigned char rx_data, tx_data;
00057 
00058 bool msb_first = true;
00059 bool edge_falling = false; // false: CPOL = 0, CPHA = 0; true: CPOL = 1, CPHA = 1
00060 bool byte_ready;
00061 int bit_count;
00062 
00063 void shift_bit(void)
00064 {
00065     if (msb_first)
00066     {
00067         rx_data = (rx_data << 1) | MOSI;
00068         MISO = (tx_data & 0x80) >> 7;
00069         tx_data <<= 1;
00070     }
00071     else
00072     {
00073         rx_data = (rx_data >> 1) | (MOSI << 7);
00074         MISO = tx_data & 1;
00075         tx_data >>= 1;
00076     }
00077     bit_count++;
00078     if (bit_count == 8)
00079     {
00080         byte_ready = true;
00081         bit_count = 0;
00082     }
00083 }
00084 
00085 void sclk_fall(void)
00086 {
00087     if (edge_falling && (PtrData == 0xfe))
00088     {
00089         shift_bit();
00090     }
00091 }
00092 
00093 void sclk_rise(void)
00094 {
00095    if (!edge_falling && (PtrData == 0xfe))
00096    {
00097         shift_bit();
00098    }
00099 }
00100 
00101 int main()
00102 {
00103 unsigned char key;
00104 bool configure_end = false;
00105 
00106     PtrData.input();
00107 
00108     /* 9600 baud serial port */
00109     pc.printf("SPI tester on mbed\r\n\n");
00110     
00111     MISO = 0;
00112     SCLK.fall(&sclk_fall);
00113     SCLK.rise(&sclk_rise);
00114     SCLK.mode(PullUp);
00115     SCLK.enable_irq();
00116     
00117     byte_ready = false;
00118     bit_count = 0;
00119     
00120     pc.printf("Actual configuration\r\n\n");
00121     pc.printf("MSB first\r\n");
00122     pc.printf("Rising edge clock\r\n\n");
00123 
00124     pc.printf("Configure\r\n\n");
00125     pc.printf("M: MSB first\r\n");
00126     pc.printf("L: LSB first\r\n");
00127     pc.printf("F: Falling edge clock\r\n");
00128     pc.printf("R: Rising edge clock\r\n");
00129     pc.printf("G: Go\r\n\n");
00130 
00131     do
00132     {
00133         key = pc.getc();    
00134     
00135         switch (key)
00136         {
00137             case 'M':
00138             case 'm':
00139                 msb_first = true;
00140                 pc.printf("MSB first\r\n");
00141                 break;
00142 
00143             case 'L':
00144             case 'l':
00145                 msb_first = false;
00146                 pc.printf("LSB first\r\n");
00147                 break;
00148                 
00149             case 'F':
00150             case 'f':
00151                 edge_falling = true;
00152                 pc.printf("Falling edge clock\r\n");
00153                 break;
00154 
00155             case 'R':
00156             case 'r':
00157                 edge_falling = true;
00158                 pc.printf("Rising edge clock\r\n");
00159                 break;
00160                 
00161             case 'G':
00162             case 'g':
00163                 configure_end = true;
00164                 break;
00165                 
00166             default:
00167             ;                        
00168         }
00169     } while (!configure_end);
00170     
00171     pc.printf("Configure end, begin test\r\n\n");
00172 
00173     while(1)
00174     {
00175         if (pc.readable())
00176         {
00177             tx_data = pc.getc();
00178         }
00179         else
00180         {
00181             if (byte_ready)
00182             {
00183                 pc.putc(rx_data);
00184                 byte_ready = false;
00185             }
00186         }  
00187     }
00188 }