CANBUS with 8MHz

[Wolfgang Kos]

Hello,

I am testing the Demo file CAN_Demo.fcfx, it will function good (20MHz).
Now i will testing with 8MHz and changed the speed under Options.
It will not function.

What can I make.

Thank you for all tipps.

Wolfgang

[Benj]

Hello,

Have you done a 1 second flasher test to ensure your hardware is running at the speed you think it is.

http://www.matrixtsl.com/wiki/index.php ... ED_flasher

How are you driving the CAN? is it internal or external to your target micro?

[Wolfgang Kos]

Hello Benj,

yes the flasher will function, the CAN is internal it will function with chrystal 20MHz.
I changed the chrystal in 8MHz and changed the Speed it will not function.
Do I Change the code manually in flowcode for the Speed, why the Speed with 20MHz is in the Code from Flowcode fixed or have you a good info?

[Benj]

Hello,

Have you changed the clock speed setting in the project options?

Also please can you post your program and I will have a look for you to see if there is anything obvious.

[Wolfgang Kos]

Hello,

yes I changed the clock Speed under Options.
I look in the C-Code the CNF and control Register will not changed automatic when I swicht from 20Mhz.to 8MHz.

//setup CNF and control registers

FC_CAN_SPI_CAN_Config_1(FCV_0e701_can1__CAN_REQOP_CONFIG);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF1, 3);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF2, 209);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF3, 3);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_TXRTSCTRL, 0);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_EFLG, 0);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CANCTRL, 0x80);
FC_CAN_SPI_CAN_Config_1(FCV_0e701_can1__CAN_REQOP_NORMAL);

Now i will ckeck a other CNF Code...
________________________________________________________________________________________________

This is the Online Demo Code I changed the processor and set the button = 1 for testing and make a Counter for Zahl, 20MHz it will good function.

Koernersensor_20MHz.fcfx

20MHz

(17.89 KiB) Downloaded 216 times

Koernersensor_8MHz_.fcfx

8MHz

(17.89 KiB) Downloaded 206 times

[QMESAR]

//setup CNF and control registers

FC_CAN_SPI_CAN_Config_1(FCV_0e701_can1__CAN_REQOP_CONFIG);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF1, 3);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF2, 209);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CNF3, 3);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_TXRTSCTRL, 0);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_EFLG, 0);
FC_CAN_SPI_CAN_Write_1(FCV_0e701_can1__CAN_CANCTRL, 0x80);
FC_CAN_SPI_CAN_Config_1(FCV_0e701_can1__CAN_REQOP_NORMAL);

This will not change if you change the Oscillator frequency ,it is the CAN baud rate registers that will only change if you change baud rate from 250Kb/sec to something else

In your setup you use 8Mhz Oscillator and HS setting which is for Crystals bigger then 10Mhz I would advise you to set it to XT not HS ,I suspect you controller is not running or not correctly

[Wolfgang Kos]

Hello I solved the Problem

I changed manualy the register Code in asm like this for 8Mhz.

MOVLW 0x05
MOVWF gbl_brgcon3
MOVLW 0xB8
MOVWF gbl_brgcon2
MOVLW 0x00
MOVWF gbl_brgcon1
MOVLB 0x0F
__________________________________________
old register Code:
MOVLW 0x03
MOVWF gbl_brgcon3
MOVLW 0xD1
MOVWF gbl_brgcon2
MOVLW 0x01
MOVWF gbl_brgcon1


This Code will not changed automatic when the clock will changed, is always the same.

I think this is a bug, can fix it or a indication that this is only for 20Mhz. CAN-Bus

[Benj]

Hello,

Thanks for letting me know how you got around the problem. I have had a look at the code and the clock speed is taken into account but only when you add the component onto your panel. Therefore changing the clock speed in a project that already had the CAN component did not work to change the baud values.

I have now fixed this so the clock speed calculation is redone whenever you compile which should hopefully solve the problem.

CAN.fcpx

(22.48 KiB) Downloaded 207 times

cal_can.fcpx

(10.14 KiB) Downloaded 224 times

The files will need to be placed here before starting Flowcode: "C:\Program Files (x86)\Flowcode 6\components"

[Wolfgang Kos]

Hello,

thank you very much... i will testing