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I am having a problem setting the Transmit ID buffers in my CAN setup. I am using the following code section: CAN0TIDR0 = tran.id[0]; CAN0TIDR1 = tran.id[1]; CAN0TIDR2 = tran.id[2]; CAN0TIDR3 = tran.id[3]; Seems simple enough. This in turn compiles into this assembly code: movb 1000, 170 movb 1001, 171 movb 1002, 172 movb 1003, 173 However, when I step through this code, it acts like nothing has happened. I can transmit packets properly, but I seem to have no control as to what I am sending out. Do I need to set a register somewhere to allow CAN registers to act as normal ones? Does the CAN0 transmit ID start at address 170 like I believe? Those are the two possible problems that I have thought of. I have attached my CAN initialization code as well below. Any help would be greatly appreciated. Thank you. Doug // Set Up Function for the CAN Controller void CAN_Setup(void) { CAN0CTL1 = 0x80; // normal operation, oscillator clock CAN0BTR0 = 0xC0; // SJW = 4, BRP = 1, 4mhz // for 24mhz CAN0BTR0 = 0xC5; // SJW = 4, BRP = 6 CAN0BTR1 = 0x49; // 1 sample, TS1 = 10, TS2 = 5 CAN0IDAR0 = 0x67; CAN0IDAR1 = 0x8A; // filter id = 0x0CF0xxxx CAN0IDAR2 = 0x00; CAN0IDAR3 = 0x00; // filter id = 0x0000xxxx CAN0IDAR4 = 0x00; CAN0IDAR5 = 0x00; // filter id = 0x0000xxxx CAN0IDAR6 = 0x00; CAN0IDAR7 = 0x00; // filter id = 0x0000xxxx CAN0IDMR0 = 0x00; CAN0IDMR1 = 0x00; // check every bit in filter CAN0IDMR2 = 0x00; CAN0IDMR3 = 0x00; // check every bit in filter CAN0IDMR4 = 0x00; CAN0IDMR5 = 0x00; // check every bit in filter CAN0IDMR6 = 0x00; CAN0IDMR7 = 0x00; // check every bit in filter CAN0CTL0 &= ~(0x01); // normal mode CAN0RFLG = 0xFF; // clear all CAN error flags CAN0RIER = 0x01; // receive interrupt enable // Synchronization Loop while (!(CAN0CTL0 & 0x10)); // wait for bus synchronization } |
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msCAN Transmit problem
Started by ●September 19, 2002
Reply by ●September 19, 20022002-09-19
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Hi Doug, CAN address 170 is the 3rd Tx buffer, is that the same one that you are transmitting data from? Is it possible that you are setting the data in one transmit buffer and transmitting a different one? Steve Zanthic Technologies Inc. is located at www.zanthic.com Your Controller Area Networking Experts! Embedded micro-controllers and CAN interface devices sold here ----- Original Message ----- From: Doug Brainard To: Sent: Thursday, September 19, 2002 4:24 PM Subject: [68HC12] msCAN Transmit problem I am having a problem setting the Transmit ID buffers in my CAN setup. I am using the following code section: CAN0TIDR0 = tran.id[0]; CAN0TIDR1 = tran.id[1]; CAN0TIDR2 = tran.id[2]; CAN0TIDR3 = tran.id[3]; Seems simple enough. This in turn compiles into this assembly code: movb 1000, 170 movb 1001, 171 movb 1002, 172 movb 1003, 173 However, when I step through this code, it acts like nothing has happened. I can transmit packets properly, but I seem to have no control as to what I am sending out. Do I need to set a register somewhere to allow CAN registers to act as normal ones? Does the CAN0 transmit ID start at address 170 like I believe? Those are the two possible problems that I have thought of. I have attached my CAN initialization code as well below. Any help would be greatly appreciated. Thank you. Doug // Set Up Function for the CAN Controller void CAN_Setup(void) { CAN0CTL1 = 0x80; // normal operation, oscillator clock CAN0BTR0 = 0xC0; // SJW = 4, BRP = 1, 4mhz // for 24mhz CAN0BTR0 = 0xC5; // SJW = 4, BRP = 6 CAN0BTR1 = 0x49; // 1 sample, TS1 = 10, TS2 = 5 CAN0IDAR0 = 0x67; CAN0IDAR1 = 0x8A; // filter id = 0x0CF0xxxx CAN0IDAR2 = 0x00; CAN0IDAR3 = 0x00; // filter id = 0x0000xxxx CAN0IDAR4 = 0x00; CAN0IDAR5 = 0x00; // filter id = 0x0000xxxx CAN0IDAR6 = 0x00; CAN0IDAR7 = 0x00; // filter id = 0x0000xxxx CAN0IDMR0 = 0x00; CAN0IDMR1 = 0x00; // check every bit in filter CAN0IDMR2 = 0x00; CAN0IDMR3 = 0x00; // check every bit in filter CAN0IDMR4 = 0x00; CAN0IDMR5 = 0x00; // check every bit in filter CAN0IDMR6 = 0x00; CAN0IDMR7 = 0x00; // check every bit in filter CAN0CTL0 &= ~(0x01); // normal mode CAN0RFLG = 0xFF; // clear all CAN error flags CAN0RIER = 0x01; // receive interrupt enable // Synchronization Loop while (!(CAN0CTL0 & 0x10)); // wait for bus synchronization } -------------------- ">http://docs.yahoo.com/info/terms/ |
Reply by ●September 20, 20022002-09-20
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For 1 you are not setting the message length Dale Kelley -----Original Message----- From: Doug Brainard [mailto:] Sent: Thursday, September 19, 2002 6:24 PM To: Subject: [68HC12] msCAN Transmit problem I am having a problem setting the Transmit ID buffers in my CAN setup. I am using the following code section: CAN0TIDR0 = tran.id[0]; CAN0TIDR1 = tran.id[1]; CAN0TIDR2 = tran.id[2]; CAN0TIDR3 = tran.id[3]; Seems simple enough. This in turn compiles into this assembly code: movb 1000, 170 movb 1001, 171 movb 1002, 172 movb 1003, 173 However, when I step through this code, it acts like nothing has happened. I can transmit packets properly, but I seem to have no control as to what I am sending out. Do I need to set a register somewhere to allow CAN registers to act as normal ones? Does the CAN0 transmit ID start at address 170 like I believe? Those are the two possible problems that I have thought of. I have attached my CAN initialization code as well below. Any help would be greatly appreciated. Thank you. Doug // Set Up Function for the CAN Controller void CAN_Setup(void) { CAN0CTL1 = 0x80; // normal operation, oscillator clock CAN0BTR0 = 0xC0; // SJW = 4, BRP = 1, 4mhz // for 24mhz CAN0BTR0 = 0xC5; // SJW = 4, BRP = 6 CAN0BTR1 = 0x49; // 1 sample, TS1 = 10, TS2 = 5 CAN0IDAR0 = 0x67; CAN0IDAR1 = 0x8A; // filter id = 0x0CF0xxxx CAN0IDAR2 = 0x00; CAN0IDAR3 = 0x00; // filter id = 0x0000xxxx CAN0IDAR4 = 0x00; CAN0IDAR5 = 0x00; // filter id = 0x0000xxxx CAN0IDAR6 = 0x00; CAN0IDAR7 = 0x00; // filter id = 0x0000xxxx CAN0IDMR0 = 0x00; CAN0IDMR1 = 0x00; // check every bit in filter CAN0IDMR2 = 0x00; CAN0IDMR3 = 0x00; // check every bit in filter CAN0IDMR4 = 0x00; CAN0IDMR5 = 0x00; // check every bit in filter CAN0IDMR6 = 0x00; CAN0IDMR7 = 0x00; // check every bit in filter CAN0CTL0 &= ~(0x01); // normal mode CAN0RFLG = 0xFF; // clear all CAN error flags CAN0RIER = 0x01; // receive interrupt enable // Synchronization Loop while (!(CAN0CTL0 & 0x10)); // wait for bus synchronization } -------------------- ">http://docs.yahoo.com/info/terms/ ------------------------ This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any unauthorized use of this email is prohibited. ------------------------ |
