CAN protocol circuit diagram

Hello Everyone!
Can someone give me a link or a pic of the exact circuit diagram to connect lp2148 to mcp 2515 (can controller) then connect it to mcp2551 (transceiver). All I can find is block diagrams.

Hello, why are you using LP2148 use some other micro controller in which CAN module come with inbuilt, that are easy to operate.

kushal nandanwar said:

Hello, why are you using LP2148 use some other micro controller in which CAN module come with inbuilt, that are easy to operate.

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As of now I have this board to work with and I am told you can work with any board. Even if i use for example lpc2129 with inbuilt can,the slave device still needs to be connected to the can controller and transceiver in order to send the information through the bus rite,so I still require the circuit diagram.

shruv said:

As of now I have this board to work with and I am told you can work with any board. Even if i use for example lpc2129 with inbuilt can,the slave device still needs to be connected to the can controller and transceiver in order to send the information through the bus rite,so I still require the circuit diagram.

Click to expand...

if u explain me your's application , then i can help you because i already worked on CAN protocol

The MCP2515 utilizes an SPI interface, you simply connect it to the LPC2148 as you would any other device with an SPI interface.

The connections between the MCP2515 and MCP2551 are even simpler, two lines TXD and RXD.

Reference: **broken link removed**

Reference: **broken link removed**

Writing or porting the code for LPC2148 to drive the MCP2515 will require the most time and effort, unless of course you can find a canned API library specifically written for the LPC21xx series.


BigDog

kushal nandanwar said:

if u explain me your's application , then i can help you because i already worked on CAN protocol

Click to expand...

Nothing much,just transfer data from one arm 7 to another arm 7 first using can bus. I wanted to know if a osc is required for mcp 2515. what are the capacitors,resistors required,because we would be rigging up the circuit,don't have a readymade can circuit board.
Which controller have you used for your can project,and how did you go about it?

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bigdogguru said:

The MCP2515 utilizes an SPI interface, you simply connect it to the LPC2148 as you would any other device with an SPI interface.

The connections between the MCP2515 and MCP2551 are even simpler, two lines TXD and RXD.

Reference: **broken link removed**

Reference: **broken link removed**

Writing or porting the code for LPC2148 to drive the MCP2515 will require the most time and effort, unless of course you can find a canned API library specifically written for the LPC21xx series.


BigDog

Click to expand...

Thanks, Rxd & txd and also Rs & Vss grounded, Vdd to 5v,is this right?
Apart from 4 spi pins,what about the osc cicuit for mcp2515,some circuit diagram they've shown the three transmit buffer connected to a resistor. not sure which one to follow.

shruv said:

Thanks, Rxd & txd and also Rs & Vss grounded, Vdd to 5v,is this right?
Apart from 4 spi pins,what about the osc cicuit for mcp2515....

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Yes, as your initial inquiry concerned the connections between LPC2148, MCP2515 and MCP2551 I omitted any discussions of V_DD, V_SS, R_S and OSC connections, all are necessary.

shruv said:

...some circuit diagram they've shown the three transmit buffer connected to a resistor. not sure which one to follow.

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Are you referring to the Transmit Buffer Request To Send (TXnRTS) lines, the MCP2515 datasheet indicates there are internal pullup resisters present on those lines and are configure using the TXRTSCTRL register.

3.5 TXnRTS PINS

The TXnRTS pins are input pins that can be configured
as:

• Request-to-send inputs, which provide an
alternative means of initiating the transmission of
a message from any of the transmit buffers

• Standard digital inputs

Configuration and control of these pins is accomplished
using the TXRTSCTRL register (see Register 3-3). The
TXRTSCTRL register can only be modified when the
MCP2515 is in Configuration mode (see Section 10.0
“Modes of Operation”). If configured to operate as a
request-to-send pin, the pin is mapped into the
respective TXBnCTRL.TXREQ bit for the transmit
buffer. The TXREQ bit is latched by the falling edge of
the TXnRTS pin. The TXnRTS pins are designed to
allow them to be tied directly to the RXnBF pins to
automatically initiate a message transmission when the
RXnBF pin goes low.

The TXnRTS pins have internal pull-up resistors of
100 k (nominal).

Click to expand...

Termination must be enabled on both devices connected to the end of the CAN bus, which is why you may see some designs with a jumper to enable or disable termination, while there are several different termination standards utilized on CAN bus designs, the most common is simple a 120Ω resister across the CANL and CANH lines.

Post the schematic portraying the design element you question, so that we may examine it.

A typical design using these components utilizing an AVR instead of the LPC follows:

**broken link removed**


BigDog

you can refer following thread
https://www.edaboard.com/threads/271911/

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you can refer following thread
https://www.edaboard.com/threads/271911/

SIR,
if in can mcp2515 tec =1 and there is sucessful 2 transfer then wuld tec decreases to -1???