Diff: main.cpp

Revision:

0:fe1f886dff76

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Mar 21 01:53:16 2012 +0000
@@ -0,0 +1,127 @@
+// CAN_MONITOR with filtering  2012/03/21 ym1784
+
+#include "mbed.h"
+#include "CAN.h"
+
+Serial pc(USBTX, USBRX); // tx, rx
+DigitalOut led2(LED2);
+
+// CAN2 on mbed pins 29(CAN_TXD) and 30(CAN_RXD) using MCP2551.
+CAN can2(p30, p29);
+
+/*--------------------------------------------
+  setup acceptance filter for CAN controller 2
+  original http://www.dragonwake.com/download/LPC1768/Example/CAN/CAN.c
+  simplified for CAN2 interface and std id (11 bit) only
+ *--------------------------------------------*/
+void CAN2_wrFilter (uint32_t id)  {
+    static int CAN_std_cnt = 0;
+    uint32_t buf0, buf1;
+    int cnt1, cnt2, bound1;
+
+    /* Acceptance Filter Memory full */
+    if (((CAN_std_cnt + 1) >> 1) >= 512)
+        return;                                       /* error: objects full */
+
+    /* Setup Acceptance Filter Configuration
+      Acceptance Filter Mode Register = Off  */
+    LPC_CANAF->AFMR = 0x00000001;
+
+    id |= 1 << 13;                        /* Add controller number(2) */
+    id &= 0x0000F7FF;                            /* Mask out 16-bits of ID */
+
+    if (CAN_std_cnt == 0)  {                     /* For entering first  ID */
+        LPC_CANAF_RAM->mask[0] = 0x0000FFFF | (id << 16);
+    }  else if (CAN_std_cnt == 1)  {             /* For entering second ID */
+        if ((LPC_CANAF_RAM->mask[0] >> 16) > id)
+            LPC_CANAF_RAM->mask[0] = (LPC_CANAF_RAM->mask[0] >> 16) | (id << 16);
+        else
+            LPC_CANAF_RAM->mask[0] = (LPC_CANAF_RAM->mask[0] & 0xFFFF0000) | id;
+    }  else  {
+        /* Find where to insert new ID */
+        cnt1 = 0;
+        cnt2 = CAN_std_cnt;
+        bound1 = (CAN_std_cnt - 1) >> 1;
+        while (cnt1 <= bound1)  {                  /* Loop through standard existing IDs */
+            if ((LPC_CANAF_RAM->mask[cnt1] >> 16) > id)  {
+                cnt2 = cnt1 * 2;
+                break;
+            }
+            if ((LPC_CANAF_RAM->mask[cnt1] & 0x0000FFFF) > id)  {
+                cnt2 = cnt1 * 2 + 1;
+                break;
+            }
+            cnt1++;                                  /* cnt1 = U32 where to insert new ID */
+        }                                          /* cnt2 = U16 where to insert new ID */
+
+        if (cnt1 > bound1)  {                      /* Adding ID as last entry */
+            if ((CAN_std_cnt & 0x0001) == 0)         /* Even number of IDs exists */
+                LPC_CANAF_RAM->mask[cnt1]  = 0x0000FFFF | (id << 16);
+            else                                     /* Odd  number of IDs exists */
+                LPC_CANAF_RAM->mask[cnt1]  = (LPC_CANAF_RAM->mask[cnt1] & 0xFFFF0000) | id;
+        }  else  {
+            buf0 = LPC_CANAF_RAM->mask[cnt1];        /* Remember current entry */
+            if ((cnt2 & 0x0001) == 0)                /* Insert new mask to even address */
+                buf1 = (id << 16) | (buf0 >> 16);
+            else                                     /* Insert new mask to odd  address */
+                buf1 = (buf0 & 0xFFFF0000) | id;
+
+            LPC_CANAF_RAM->mask[cnt1] = buf1;        /* Insert mask */
+
+            bound1 = CAN_std_cnt >> 1;
+            /* Move all remaining standard mask entries one place up */
+            while (cnt1 < bound1)  {
+                cnt1++;
+                buf1  = LPC_CANAF_RAM->mask[cnt1];
+                LPC_CANAF_RAM->mask[cnt1] = (buf1 >> 16) | (buf0 << 16);
+                buf0  = buf1;
+            }
+
+            if ((CAN_std_cnt & 0x0001) == 0)         /* Even number of IDs exists */
+                LPC_CANAF_RAM->mask[cnt1] = (LPC_CANAF_RAM->mask[cnt1] & 0xFFFF0000) | (0x0000FFFF);
+        }
+    }
+    CAN_std_cnt++;
+
+    /* Calculate std ID start address (buf0) and ext ID start address <- none (buf1) */
+    buf0 = ((CAN_std_cnt + 1) >> 1) << 2;
+    buf1 = buf0;
+
+    /* Setup acceptance filter pointers */
+    LPC_CANAF->SFF_sa     = 0;
+    LPC_CANAF->SFF_GRP_sa = buf0;
+    LPC_CANAF->EFF_sa     = buf0;
+    LPC_CANAF->EFF_GRP_sa = buf1;
+    LPC_CANAF->ENDofTable = buf1;
+
+    LPC_CANAF->AFMR = 0x00000000;                  /* Use acceptance filter */
+} // CAN2_wrFilter
+
+int main() {
+    pc.baud(921600);
+    pc.printf("CAN_MONITOR 921600 bps\r\n");
+
+    // 500kbit/s
+    can2.frequency(500000);
+    CANMessage can_MsgRx;
+
+    CAN2_wrFilter(0x0B4);
+    CAN2_wrFilter(0x1C4);
+    CAN2_wrFilter(0x245);
+    CAN2_wrFilter(0x3D3);
+    CAN2_wrFilter(0x498);
+    CAN2_wrFilter(0x4A6);
+
+    while (1) {
+        // send received messages to the pc via serial line
+        if (can2.read(can_MsgRx)) {
+            pc.printf("t%03X%d", can_MsgRx.id, can_MsgRx.len);
+            for (char i=0; i<can_MsgRx.len; i++) {
+                pc.printf("%02X", can_MsgRx.data[i]);
+            } // for
+            pc.printf("\r\n");
+            // toggle led2
+            led2 = !led2;
+        } // if
+    } // while
+} // main