Good Morning,
I have 2 issues with programming the MPC5777C.
First One:
-> I want tu use the CAN_FD Option from M_CAN_0 (ISO CAN Works already)
so i Change the Parameter for can FD with and withouth Bitrate switching from example.
In my Init i wait for CCCR.INIT and CCCR.CCE for Setting 0.
After this Operation, i make the cmr request and set the can Mode with cme. The CCCR.CME bit is set in Expression view. On the other side the CCCE.FDBS and CCCR.FDO bits for the request are set no time.
#if XXX_MCAN_L_BRS_DEF
M_CAN_0.CCCR.B.CMR = 0x2; // enable CAN FD with bit rate switching
M_CAN_0.CCCR.B.CME = 0x2;
M_CAN_0.BTP.B.BRP = 1u; //4
M_CAN_0.BTP.B.SJW = 3u;
M_CAN_0.BTP.B.TSEG1 = 4u; //12
M_CAN_0.BTP.B.TSEG2 = 2u; //0
M_CAN_0.FBTP.B.FBRP = 0x0u;
M_CAN_0.FBTP.B.FSJW = 0x3u;
M_CAN_0.FBTP.B.FTSEG1 = 0x4u;
M_CAN_0.FBTP.B.FTSEG2 = 0x2u;
#else
M_CAN_0.CCCR.B.CMR = 0x1; // enable CAN FD without bit rate switching
M_CAN_0.CCCR.B.CME = 0x1;
M_CAN_0.BTP.R = 0x00011E77; // Set time quanta for 0.5Mbps
M_CAN_0.BTP.B.SJW = 5;
M_CAN_0.BTP.B.TSEG1 = 16;
M_CAN_0.BTP.B.TSEG2 = 1;
#endif
My Second issue is, that the MCAN clock is wrong. If i calculate the frequency back from my Settings, i recieve a frequency from 8.1 MHz. But i have choose xosc as clock source and Programm the extal pin in the dcf(XOSCEN=0) record as xosc. There is a 40MHz oscillator connected to this pin. So i don´t know why the freuency is so low.
SIU.SYSDIV.B.MCANSEL = 0;
SIU.HLT2.B.MCANA = 0;
SIU.HLT2.B.MCANB = 0;
已解决! 转到解答。
Hi Marcus,
the example posted on the community was created and tested on previous MCU cut (2N45H).
There are several changes in registers between versions, so if you have latest one, you should follow latest RM for a proper registers definition. A MPC5777CRMAD (https://www.nxp.com/docs/en/reference-manual/MPC5777CRMAD.pdf) have to be used when using 2N45H mask.
for a CCCR register
3N45H
2N45H
so the code on latest revision could be as below
// put module to Init mode
MCAN_0.CCCR.B.INIT = 0x1;
while(MCAN_0.CCCR.B.INIT == 0) { asm("nop"); }
// enable CCE bit to change config
MCAN_0.CCCR.B.CCE = 0x1;
while(MCAN_0.CCCR.B.CCE==0) { asm("nop"); }
#if BRS
MCAN_0.CCCR.B.FDOE = 0x1; // enable CAN FD
MCAN_0.CCCR.B.BRSE = 0x1; // enable bit rate switching
....
#else
MCAN_0.CCCR.B.FDOE = 0x1; // enable CAN FD
MCAN_0.CCCR.B.BRSE = 0x0; // disable bit rate switching
....
#endif
For a CAN bit timing again there is significant difference in registers. On 3N45H registers are named NBTP and DBTP (TDCR if TDC is also enabled) while on 2N45H it was BTP and FBTP. So you must set it properly to have correct timing.
BR, Petr
Hi Marcus,
the example posted on the community was created and tested on previous MCU cut (2N45H).
There are several changes in registers between versions, so if you have latest one, you should follow latest RM for a proper registers definition. A MPC5777CRMAD (https://www.nxp.com/docs/en/reference-manual/MPC5777CRMAD.pdf) have to be used when using 2N45H mask.
for a CCCR register
3N45H
2N45H
so the code on latest revision could be as below
// put module to Init mode
MCAN_0.CCCR.B.INIT = 0x1;
while(MCAN_0.CCCR.B.INIT == 0) { asm("nop"); }
// enable CCE bit to change config
MCAN_0.CCCR.B.CCE = 0x1;
while(MCAN_0.CCCR.B.CCE==0) { asm("nop"); }
#if BRS
MCAN_0.CCCR.B.FDOE = 0x1; // enable CAN FD
MCAN_0.CCCR.B.BRSE = 0x1; // enable bit rate switching
....
#else
MCAN_0.CCCR.B.FDOE = 0x1; // enable CAN FD
MCAN_0.CCCR.B.BRSE = 0x0; // disable bit rate switching
....
#endif
For a CAN bit timing again there is significant difference in registers. On 3N45H registers are named NBTP and DBTP (TDCR if TDC is also enabled) while on 2N45H it was BTP and FBTP. So you must set it properly to have correct timing.
BR, Petr