topic Re: CAN Implementation using lpc1768 in LPC Microcontrollers

CAN Implementation using lpc1768

Mithunv — Tue, 24 Aug 2021 09:35:54 GMT

Hi Nxp support team,

I am trying to use lcp1768 is normal operation mode and transmit a CAN message through it.

currently I am facing transmit error issue whenever I try to transmit a message.

i.e as soon as LPC_CAN1->CMR = 0x21; register is set to the value 0x21 I am seeing can mode getting set to reboot and ICR register is having 0x0030000 values which is nothing but start of frame error.

hardware connections

From LPC1768 i am connecting CAN1 tx to mcp2551 tx and LPC1768 rx i am connecting it to mcp2551 rx .

Currently i am using coocox ide and i have attached my complete project .

Please let me know where is the problem.

Re: CAN Implementation using lpc1768

frank_m — Tue, 24 Aug 2021 13:06:26 GMT

> register is set to the value 0x21 I am seeing can mode getting set to reboot and ICR register is having 0x0030000 values which is nothing but start of frame error.

I suppose that would point to a hardware issue. I am not very proficient with the LPC176x CAN peripherla, though. A CAN node creates an error when it is unable to get a message out, e.g. there is no other device on the bus.

You can try loopback mode (connect Tx and Rx, not sure if it's directly supported by the LPC176x), or connect two devices directly on board logic level (Rx->Tx, Tx->Rx, and GND).

Hi Nxp support team, ...

While some NXP staff members are active here, a lot of posters (like me) are NXP users and volunteers, and not affiliated with NXP. This is an open forum, hosted by NXP.

The main difference is, no answer guaranteed.

Re: CAN Implementation using lpc1768

Alice_Yang — Fri, 27 Aug 2021 01:34:13 GMT

Hello Mithunv,

First confirm, have you connect to another CAN Node with your LPC1768 CAN?

There is CAN demo based on lpc1769 under LPCopen, recommend you first to refer to.

https://www.nxp.com/design/microcontrollers-developer-resources/lpcopen-libraries-and-examples/lpcopen-software-development-platform-lpc17xx:LPCOPEN-SOFTWARE-FOR-LPC17XX

Alice