Hi , i work with LPC1549. The Usb bus fonction correctly , but not the Can Bus .
When i send a Can transmission to the computer I Watch the TxCan signal with a scoop
but there are no signal and the computer say me " TX empty". When i want send a message from computer to the board
I see the signal with a scoop but the mail box is empty too. I think i have a problem of Can initialisation...
See my schematic and program initialisation Can you help me please....
See My Initialisation Programm
Hi Olivier,
Thank you for your updated information, and that's very good to hear your problem is solved.
Actually, the lpcopen code is connected to the PIO0_11 and PIO0_31, so if you want to use PIO0_13 and PIO0_18, you need to modify the code.
Have a great day,
Kerry
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Hi ...
But i already use the lpcopen code of My Mcuxpresso 10.0.034...
I have already see on the forum that there are some Problèmes of transmission with LPC1549JBD48 and CAN...
The code is the code of C_CANROM of lpc 1549. I have juste changing the Number of the CAN PIN
( PIO13 for RDCan and PIO18 for TDCan).... You can see...
About the hard i have made the same think that you....
I use the Muxtrace of exotest and the reponse is NO ACK... when i want send the data to the lpc
and when i want send from lpc to muxtrace... no transmission... I think there are somethink to do
in the initialisation Lpc.. Like if the can module is not powered... I don' t Known....
Can you send me your initialisation can Programme.. Please...
HI Kerry.
I have take an other lpc1549 board . iuse lpcopen CANrom
My environnement is now :
I have alway not signal to my output . My LPC is LPC1549 _48 with pio13 and pio18 like CANRX and CANTX.
My code is very sample and the up don' t stop. here...
1°) Have you an Idée of my problem ?
2°) Have you a documention for the calculation of baud rate ?
Hi Olivier POHU,
Please accept my apologies for the late reply, because recently, I am a little overloaded, now, I reply you in details after the test.
1. LPCXpress 1549 CAN_TX have no signal after run the periph_ccan_rom
This problem is caused by no CAN transceiver in the hardware, the CAN_TX pin need to associate with the CAN transceiver, then we can get the CAN transmit data.
2. My test result details.
Board: LPCXpress LPC1549
Code: lpcopen_2_20_lpcxpresso_nxp_lpcxpresso_1549\periph_ccan_rom
CAN transceiver: I connect a external CAN transceiver, the circuit is like follows:
I connect the LPCXpresso LPC1549 CAN_TX to C_TXD, CAN_RX to C_RXD. CANH and CANL connect to my CAN analyzer(PEAK CAN).
Test tool:
CAN analyzer: PEAK CAN
Oscilloscope, test the CAN_TX, CAN_H and CAN_L wave.
Wave:
1) CAN_TX, CAN_H, CAN_L oscilloscope wave
Channel 1: CAN_TX ; Channel 2: CAN_H; Channel 3: CAN_L
Zoom in it.
You can find the bit rate is 500Kps, just as the code defined.
2) CAN analyzer data
After the board reset, you can find the CAN analyzer can receive the standard ID 0x345, data is 0x54 0x45, 0x53, 0x54, just as the transmit code:
/* Send a simple one time CAN message */
msg_obj.msgobj = 0;
msg_obj.mode_id = 0x345;
msg_obj.mask = 0x0;
msg_obj.dlc = 4 ;
msg_obj.data[0] = 'T'; /* 0x54 */
msg_obj.data[1] = 'E'; /* 0x45 */
msg_obj.data[2] = 'S'; /* 0x53 */
msg_obj.data[3] = 'T'; /* 0x54 */
Then, use the CAN analyzer send the CAN data, standard ID: 0X400, data is 0X00, 0X01,0X02,0X03,0X04,0X05,0X06,0X07.From the code:
static void CAN_rx(uint8_t msgNumber)
{
/* Determine which CAN message has been received */
msg_obj.msgobj = msgNumber;
/* Now load up the msg_obj structure with the CAN message */
LPC_CAND_API->hwCAN_MsgReceive(pCanHandle, &msg_obj);
if (msgNumber == 1) {
/* Simply transmit CAN frame (echo) with with ID +0x100 via buffer 2 */
msg_obj.msgobj = 2;
msg_obj.mode_id += 0x100;
LPC_CAND_API->hwCAN_MsgTransmit(pCanHandle, &msg_obj);
}
}
We can find after the LPC1549 receive the CAN data, it will add 0x100 to the received ID, then send the data back the CAN bus.
Look the above pictures, you can find the CAN analyzer received the 0X500 standard ID, it is 0X400+0X100, it is correct.
All the above data and waves meas the lpcopen can code works, both the send and receive.
So, I think you problem may be caused by your CAN transceiver hardware, if the CAN transceiver hardware have problem, you won't get the correct data or test the correct wave.
You can refer to may CAN transceiver circuit to try it.
Wish it helps you!
If you still have question about it, please let me know!
Have a great day,
Kerry
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Hi Kerry , Thanks very much for your help .You can see my test environnement on the drawwing.
Yes i have already use LpcOpen , but that do the same think....
Have you the formule for calculate baud rate and % Point evironnemnent on LPC1549 ?
I send my Trame with 500K 87% and the Lpc1549 is programmed à 500K 87,5 % ( 0x502) ?
But i have no information for baud rate calculation .. Perhaps it is that ?
Thank for your help Kerry..
