CAN Communication

Gautan Thank You for replying , i went through the structure and even the code, but i am not able to code such that each parameter enters the specific mail box for example parameter 1 in mailbox 0, parameter 2 in mailbox 1,... so on .

Thank You.

Gautam Thank You so much. I apologize for asking such an innocent question. Thank You Again. 

I ll get back to you further if i have any doubts. 

Thank You Again.

Hi Gautam, I read this post where a guy wants to access 15 strings of data coming from battery and he also doesn't know the message ids of that data. And you have provided him with this answer . Can you explain it , I coudn't understand the difference between his and my problem although it seems similar. 

Your reply:

You can mask all the MsgID bits to receive to a particular Mailbox. Simply Set AME bit and configure ECanaLAMRegs.LAM2.all = 0xFFFFFFFF;

for mailbox 2.

By this can i see all the 15 parameters in a single mailbox and use the specific parameter?

Thank You so much Gautam.

You're Welcome!

Goodluck & Regards,
Gautam

Hello Gautam,
this is the code i am using to read the data.

//
// Lab11_2: TMS320F28335
// (c) Frank Bormann
//
//###########################################################################
//
// FILE: Lab11_2.c
//
// TITLE: CAN - Receive via F28335controlCARD
// and SH65HVD230 at Peripheral Explorer Board
//
// Extended CAN-Frame is received with 100 kbit/s
//
// Objective:
// Receive a 1 Byte data frame with Identifier 0x10000000
// and display 4 least significant bits of byte0 at 4 LEDs
//
// Mailbox 1 is receiver
// Identifier : 0x1000 0000
// Data Length Code (DLC) = 1
// eCANA is at GPIO31 (CANTXA) and GPIO30 (CANRXA)
//
// Frequency Osscillator @F28335controlCARD: 30MHz
// PLLCR = 10 : multiply by 5
// SYSCLKOUT = 150MHz , 28335-CAN-CLKIN = 75MHz
// CAN - Bit timing set in file "DSP2833x_ECan.c" for 100 kbit/s:
// TQ = (49 +1) / 75 MHz = 0.667 us: BRPREG = 49
// tseg1 = 1us (10+1) = 7.333 us; TSEG1REG = 10
// tseg2 = 1us (2+1) = 2 us; TSEG2REG = 2
//###########################################################################
// Ver | dd mmm yyyy | Who | Description of changes
// =====|=============|======|===============================================
// 3.0 | 14 Jul 2009 | F.B. | solution file Lab11_2 for F28335;
// 3.1 | 15 Nov 2009 | F.B | Lab11_2 for F28335 @30MHz and PE revision 5
//###########################################################################
#include "DSP2833x_Device.h"

// external function prototypes
extern void InitSysCtrl(void);
extern void InitPieCtrl(void);
extern void InitPieVectTable(void);
extern void InitCpuTimers(void);
extern void ConfigCpuTimer(struct CPUTIMER_VARS *, float, float);
extern void InitECan(void);


// Prototype statements for functions found within this file.
void Gpio_select(void);
interrupt void cpu_timer0_isr(void);

//###########################################################################
// main code
//###########################################################################
void main(void)
{
struct ECAN_REGS ECanaShadow; // local copy of CAN registers
Uint16 temp;

InitSysCtrl(); // Basic Core Init from DSP2833x_SysCtrl.c

EALLOW;
SysCtrlRegs.WDCR= 0x00AF; // Re-enable the watchdog
EDIS; // 0x00AF to NOT disable the Watchdog, Prescaler = 64

Gpio_select(); // GPIO9, GPIO11, GPIO34 and GPIO49 as output
// to 4 LEDs at Peripheral Explorer

/* Initialize the CAN module */
// NOTE: first modify TI-file: InitECan() to 100kbps by setting BTR = 49
InitECan();

/* Write to Mailbox 1 message ID field */
ECanaMboxes.MBOX1.MSGID.all = 0x10000000; // extended identifier
ECanaMboxes.MBOX1.MSGID.bit.IDE = 0;

/* Configure Mailbox 1 as Receiver mailbox */
ECanaShadow.CANMD.all = ECanaRegs.CANMD.all;
ECanaShadow.CANMD.bit.MD1 = 1;
ECanaRegs.CANMD.all = ECanaShadow.CANMD.all;

/* Enable Mailbox 1 */
ECanaShadow.CANME.all = ECanaRegs.CANME.all;
ECanaShadow.CANME.bit.ME1 = 1;
ECanaRegs.CANME.all = ECanaShadow.CANME.all;

InitPieCtrl(); // basic setup of PIE table; from DSP2833x_PieCtrl.c

InitPieVectTable(); // default ISR's in PIE

EALLOW;
PieVectTable.TINT0 = &cpu_timer0_isr;
EDIS;

InitCpuTimers(); // basic setup CPU Timer0, 1 and 2

ConfigCpuTimer(&CpuTimer0,150,100000);

PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

IER |=1;

EINT;
ERTM;

CpuTimer0Regs.TCR.bit.TSS = 0; // start timer0

while(1)
{
//while(CpuTimer0.InterruptCount == 0);
//CpuTimer0.InterruptCount = 0;

EALLOW;
SysCtrlRegs.WDKEY = 0x55; // service WD #1
EDIS;
temp = ECanaMboxes.MBOX1.MDL.byte.BYTE0;

if(ECanaRegs.CANRMP.bit.RMP1 == 1 ) // valid new data in MBX1?
{
// read message
ECanaRegs.CANRMP.bit.RMP1 = 1; // clear the status flag RMP1
// and prepare MBX1 for next receive
if(temp & 1) // update LED LD1
GpioDataRegs.GPASET.bit.GPIO9 = 1;
else
GpioDataRegs.GPACLEAR.bit.GPIO9 = 1;
if(temp & 2) // update LED LD2
GpioDataRegs.GPASET.bit.GPIO11 = 1;
else
GpioDataRegs.GPACLEAR.bit.GPIO11 = 1;
if(temp & 4) // update LED LD3
GpioDataRegs.GPBSET.bit.GPIO34 = 1;
else
GpioDataRegs.GPBCLEAR.bit.GPIO34 = 1;
if(temp & 8) // update LED LD4
GpioDataRegs.GPBSET.bit.GPIO49 = 1;
else
GpioDataRegs.GPBCLEAR.bit.GPIO49 = 1;
}
}
}

void Gpio_select(void)
{
EALLOW;
GpioCtrlRegs.GPAMUX1.all = 0; // GPIO15 ... GPIO0 = General Puropse I/O
GpioCtrlRegs.GPAMUX2.all = 0; // GPIO31 ... GPIO16 = General Purpose I/O
GpioCtrlRegs.GPAMUX2.bit.GPIO30 = 1; // CANA_RX
GpioCtrlRegs.GPAMUX2.bit.GPIO31 = 1; // CANA_TX

GpioCtrlRegs.GPBMUX1.all = 0; // GPIO47 ... GPIO32 = General Purpose I/O
GpioCtrlRegs.GPBMUX2.all = 0; // GPIO63 ... GPIO48 = General Purpose I/O
GpioCtrlRegs.GPCMUX1.all = 0; // GPIO79 ... GPIO64 = General Purpose I/O
GpioCtrlRegs.GPCMUX2.all = 0; // GPIO87 ... GPIO80 = General Purpose I/O

GpioCtrlRegs.GPADIR.all = 0;
GpioCtrlRegs.GPADIR.bit.GPIO9 = 1; // peripheral explorer: LED LD1 at GPIO9
GpioCtrlRegs.GPADIR.bit.GPIO11 = 1; // peripheral explorer: LED LD2 at GPIO11

GpioCtrlRegs.GPBDIR.all = 0; // GPIO63-32 as inputs

GpioCtrlRegs.GPBDIR.bit.GPIO34 = 1; // peripheral explorer: LED LD3 at GPIO34
GpioCtrlRegs.GPBDIR.bit.GPIO49 = 1; // peripheral explorer: LED LD4 at GPIO49

GpioCtrlRegs.GPCDIR.all = 0; // GPIO87-64 as inputs
EDIS;
}

interrupt void cpu_timer0_isr(void)
{
CpuTimer0.InterruptCount++;
EALLOW;
SysCtrlRegs.WDKEY = 0xAA; // service WD #2
EDIS;
PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}
//===========================================================================
// End of SourceCode.
//===========================================================================

We have message identifier as 0x356, 0x355 and the source has provided the same message id for different parameter which each parameter assigned different byte position; so how do we know whether its extended identifier or standard identifier.
And this is the connection i have made CAN TX from transceiver to GPIO31 (CANTXA) and CAN RX from transceiver to GPIO30 (CANRXA).

Smitesh Modak said:

so how do we know whether its extended identifier or standard identifier.

Simply check the IDE field in MSGID

When AMI = 1:

IDE = 1: The RECEIVED message had an extended identifier

IDE = 0: The RECEIVED message had a standard identifier

Regards,

Gautam

Hi Gautam,

I have a problem with my F28379D. When I programmed it with Simulink to transmit data over CAN I get this waveform on oscilloscope which is weird.

It is supposed to be differential but CAN high and low are identical. that's why I can't read it through CANalyzer or other devices. Do you have any idea?

Thanks,

Kash

Hi Kash,

Please don't post your queries in old threads. Create a new one for better support.
Replied here: e2e.ti.com/.../2119142

Regards,
Gautam