Changes between Version 1 and Version 2 of Docs/Prog/Manual/DeviceSupport/SerialPorts

Timestamp:

11/30/09 10:21:43 (15 years ago)

Author:

Don Wilson

Comment:

--

Docs/Prog/Manual/DeviceSupport/SerialPorts

@@ -1 +1 @@
 == Serial Ports ==
+
+=== Using Serial Ports for Linux Shell ===
+By default, the Cardinal 825 ships with the Linux console disabled. To enable it, start the indicator and press 3. Setup Menu. Next, press 4. Update Software Menu and then 3. Settings. If you see '''console=null''', remove that line. Save the settings and reboot your indicator. You will now see Linux output from COM1.
+
+=== Generic Serial Port Use ===
+The “COM1” and “COM2” serial ports are routed through the main board to the MCF5329 processor on the operator interface board. These ports are controlled by the appropriate uCLinux device driver for the built in Coldfire serial ports. These ports may be accessed as:
+
+/dev/ttyS0  = COM1
+/dev/ttyS1  = COM2
+
+For example you may test from the serial terminal by typing:
+{{{
+# echo “Hello” > /dev/ttyS1
+}}}
+
+This will send the message “Hello” out the COM2 serial port. The 825 COM3 port is connected to the main board MCF5213 processor. If the 825 is configured for OIML operation this port is dedicated to sending OIML format verification weight and may not be used by applications. If OIML is not enabled applications may access the COM3 port by means of the mnbd-comm device driver. For example:
+
+{{{
+# echo “H313233” > /dev/mnbd
+}}}
+
+This will output “123” to the COM3 port. Note 31 hexadecimal for the ASCII character “1”, 32 is hexadecimal for the ASCII character “2”, etc. As of kernel 2008-11-20 an additional device file /dev/com3 is provided to simplify COM3 application communications. This additional device file is also controlled by the mnbd-comm device driver.
+{{{
+# echo “123” > /dev/com3
+}}}
+
+This will output “123” to the COM3 port.
+
+To perform a similar operations within a C program you may use code similar to:
+
+{{{
+#!Lineno
+#!c
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main()
+{
+   FILE* pFile = fopen("/dev/ttyS1", "w");
+   if(pFile != NULL)
+   {
+      fprintf(pFile, "123\r\n");
+      fclose(pFile);
+   }
+}
+
+}}}
+
+This will write to COM2. Note fprintf also allows format specifiers such as %d to be used:
+
+{{{
+    int nID = 240;
+    fprintf(pFile, "ID: %d\r\n", nID);
+}}}
+
+This would output "ID: 240".
+
+You may want a program that reads the serial port and responds:
+
+{{{
+#!Lineno
+#!c
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <string.h>
+
+#include <math.h>
+#include <time.h>
+
+#include <signal.h>
+
+#include <termios.h>
+
+#include "lcd.h"
+
+#include "touch.h"
+#include "kypdbeep.h"
+#include "form.h"
+#include "mnbdcomm.h"
+#include "login.h"
+
+extern uint32 g_nRepWtIntv;
+
+extern struct mnbd_wt_struct wtdata[MAX_SCALES];
+extern uint32 g_nRepWtIntv;
+extern unsigned char g_nRepWtTst;
+
+extern int g_keycnt;
+extern uint8 g_keybuf[20];
+
+#define TIME_FREQ       100
+#define SLP_FREQ        10
+#define DSP_FREQ        10
+
+// On terminal send ACK (CTRL-F) - 825 will send back "ACK received"
+// On terminal send NACK (CTRL-U) - 825 will send back "NACK received"
+// On terminal send STX (CTRL-B) - 825 will start buffering received data
+// On termainl send ETX (CTRL-C) - 825 will send back data received and stop buffering
+
+
+// ttyS1 = COM2
+#define SERIAL_PORT "/dev/ttyS1"
+#define ACK                     0x06
+#define NACK            0x15
+#define STX                     0x02
+#define ETX                     0x03
+
+#define ACK_RESPONSE            "ACK received\r\n"
+#define ACK_RESPONSE_LEN        strlen(ACK_RESPONSE)
+
+#define NACK_RESPONSE           "NACK received\r\n"
+#define NACK_RESPONSE_LEN       strlen(NACK_RESPONSE)
+
+
+int main(int argc, char* argv[])
+{
+   int n;
+   char szMsg[41];
+   struct timespec delaytm;
+
+   int i, nFile;
+   struct termios options;
+   unsigned char rcvdata[11];
+
+   char rcv_buf[50];
+   unsigned int rcv_buf_pos = 0;
+   enum { rcv_idle, rcv_cmd };
+   int rcv_mode = rcv_idle;
+    
+   nFile = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NONBLOCK);
+   tcgetattr(nFile, &options);
+   options.c_iflag = IGNBRK | IGNPAR;
+   options.c_cflag = CS8 | CREAD | CLOCAL | CRTSCTS;
+   options.c_lflag = 0;
+   options.c_oflag = 0;
+   options.c_cc[VMIN] = 1;
+   options.c_cc[VTIME] = 0;
+   tcsetattr(nFile, TCSADRAIN, &options);
+        
+   delaytm.tv_sec = 0;
+   delaytm.tv_nsec = 100000;
+        
+   ReadTouchCal();
+
+   OpenBeeper();
+
+   OpenMnBd(0); // Mainboard settings
+        
+   OpenTouch();
+        
+   InitLCD();
+
+   OpenMnBd(REQ_SCALE(1));
+        
+   g_nRepWtIntv = REP_INTV_SAMPLE_RATE;
+   MnBdRequest(REQ_SCALE(1), MNBD_REQ_REP_WT, NO_WAIT_ACK);
+
+   int tm_cnt = TIME_FREQ;
+   int slp_cnt = SLP_FREQ;
+   int dsp_cnt = DSP_FREQ;
+
+   while(1)
+   {
+      slp_cnt--;
+      if(slp_cnt == 0)
+      {
+          nanosleep(&delaytm, NULL);
+          slp_cnt = SLP_FREQ;
+      }
+        
+      if(ind_check_for_wt_rcv(1))
+      {
+          dsp_cnt--;
+          if(dsp_cnt == 0)
+          {
+              LocateLCD(0,0);
+              sprintf(szMsg, "%6.2f", wtdata[1].grosswt);
+              PrintLCD(szMsg);
+
+              ReadKeypad();
+              if(g_keycnt > 0)
+              {
+                  g_keycnt = 0;
+                  if(g_keybuf[0] == ESC)
+                      break;
+              }
+              dsp_cnt = DSP_FREQ;
+          }
+      }
+
+      int n = read(nFile, rcvdata, sizeof(rcvdata));
+      for(i = 0; i < n; i++)
+      {
+         if(rcvdata[i] == ACK)
+         {
+            // Handle ACK
+            write(nFile, ACK_RESPONSE, ACK_RESPONSE_LEN);
+            rcv_mode = rcv_idle;
+         }
+         else if(rcvdata[i] == NACK)
+         {
+            // Handle NACK
+            write(nFile, NACK_RESPONSE, NACK_RESPONSE_LEN);
+            rcv_mode = rcv_idle;
+         }
+         else if(rcv_mode == rcv_idle)
+         {
+            if(rcvdata[i] == STX)
+            {
+               rcv_mode = rcv_cmd;
+               rcv_buf_pos = 0;
+            }
+         }
+         else if(rcv_mode == rcv_cmd)
+         {
+            if(rcvdata[i] == ETX)
+            {
+               // Command received - write it 
+               write(nFile, rcv_buf, rcv_buf_pos);
+               rcv_mode = rcv_idle;
+            }
+            else
+            {
+               if(rcv_buf_pos < sizeof(rcv_buf) - 1)
+               {
+                  rcv_buf[rcv_buf_pos++] = rcvdata[i];
+               }
+            }
+         }
+       }
+    }
+    g_nRepWtIntv = REP_INTV_STOP;
+    MnBdRequest(REQ_SCALE(0), MNBD_REQ_REP_WT, NO_WAIT_ACK);
+
+    CloseMnBd(0);
+    CloseMnBd(REQ_SCALE(1));
+    ClearLCD();
+    return 0;
+}
+
+}}}
+
+This sample displays updating weight on the LCD display and will exit when the Shift-ESC key on the keypad is pressed. If CTRL-F is received on the COM2 port this application will send "ACK received<CR><LF>" out the serial port in response. If CTRL-U is received on the COM2 port this application will send "NACK received<CR><LF>" out the serial port in response. If CTRL-B is received the application will start buffering subsequent received characters. When CTRL-C is received the application will respond back with the buffered characters and stop buffering.
+
+[[Top]]