Question
SPC570s-DISP board: FlexCAN sends bad frames independent of CAN parameters
Hello,
I have similar problem with the SP570S-DISP board as described here:
My Configuration: 250KBaud, 16Tq, Sample-point=75%, XOSC 40MHz, CAN_clk 40 MHz, V_ext=12V/VDD_HV_IO=5V, Vector VN1610+CANoe running, 120 Ohm on both sides, ID=0x135, Data={0xAA, 0x55, 0x00, 0x00, 0xAA, 0x55, 0x00, 0x00} DLC=8.
Clock settings:
/* Setting the system dividers to their final values.*/
/*
* b0 : DE = 0b1 enable divider
* b9-15 : DIV (Divider is DIV + 1)
*/
/* System clock 0 divider */
MC_CGM.SC_DC0.R = 0x80000000UL;
/* System clock 1 divider */
MC_CGM.SC_DC1.R = 0x80010000UL;
/* System clock 2 disabled */
MC_CGM.SC_DC2.R = 0UL;
/* Pit clock divider 5 */
MC_CGM.AC0_DC0.R = 0x80040000UL;
/* SAR ADC clock divider 25 */
MC_CGM.AC0_DC1.R = 0x80180000UL;
/* CTU clock divider 25 */
MC_CGM.AC0_DC2.R = 0x80180000UL;
/* DSPI clock divider 4 */
MC_CGM.AC0_DC3.R = 0x80030000UL;
/* LinFlex clock disabled */
MC_CGM.AC0_DC4.R = 0UL;
/* eTimer clock divider 4*/
MC_CGM.AC0_DC5.R = 0x80030000UL;
/* FlexCAN clock divider 1 */
MC_CGM.AC1_DC0.R = 0x80000000UL;
/* Setting the clock selectors for PIT, SAR, CTU, DSPI, LinFlex, eTimer: PLL_0 */
/*
* b4-7: SELCTL (Auxiliary clock source selection control)
* */
MC_CGM.AC0_SC.R = 0x02000000UL;
/* Setting the clock selectors for FlexCAN: XOSC (external oscillator) */
MC_CGM.AC1_SC.R = 0x01000000UL;
/* Setting the clock selectors for PLL_0: XOSC (external oscillator) */
MC_CGM.AC2_SC.R = 0x01000000UL;
/* Setting the clock selectors for PLL_1: XOSC (external oscillator) */
MC_CGM.AC3_SC.R = 0x01000000UL;FlexCAN settings:
uint8_t mb_index = 0;
/* set peripheral clock mode.*/
cpu_set_peripheral_clock_mode(79U, 0x12);
/* external clock source */
FLEXCAN_0.CTRL.B.CLK_SRC = 1U;
/* Empty all mailboxes */
for (mb_index = 0; mb_index < 8U; mb_index++) {
FLEXCAN_0.MB[mb_index].MB_CS.R = 0UL;
FLEXCAN_0.MB[mb_index].MB_ID.R = 0UL;
FLEXCAN_0.MB[mb_index].MB_DATAL.R = 0UL;
FLEXCAN_0.MB[mb_index].MB_DATAH.R = 0UL;
}
/* Enable the device.*/
FLEXCAN_0.MCR.B.MDIS = 0U;
while (0 == FLEXCAN_0.MCR.B.LPM_ACK)
;/* wait until module is enabled */
FLEXCAN_0.MCR.B.FRZ = 0b1;
FLEXCAN_0.MCR.B.HALT = 0b1;
while (0 == FLEXCAN_0.MCR.B.FRZ_ACK)
;/* enter freeze mode */
FLEXCAN_0.MCR.B.MAXMB = 7U;
FLEXCAN_0.MCR.B.SUPV = 0b0; /* deactivate super-visor mode */
FLEXCAN_0.MCR.B.SRX_DIS = 0b1; /* No self reception*/
FLEXCAN_0.MCR.B.FEN = 0b0; /* No Fifo */
FLEXCAN_0.MCR.B.AEN = 0b0; /* No Abort enable */
FLEXCAN_0.MCR.B.WRN_EN = 0b1;
FLEXCAN_0.MCR.B.LPRIO_EN = 0b0; /* no prio */
(void) FLEXCAN_0.TIMER.R; /* Unlock message buffer */
/* RX MB initialization.*/
for (mb_index = 0U; mb_index < 4U; mb_index++) {
FLEXCAN_0.MB[mb_index].MB_CS.B.CODE = 4U;
}
/* TX MB initialization.*/
for (mb_index = 4U; mb_index < 8U; mb_index++) {
FLEXCAN_0.MB[mb_index].MB_CS.B.CODE = 8U;
}
FLEXCAN_0.CTRL.B.PSEG1 = 5U;
FLEXCAN_0.CTRL.B.PSEG2 = 3U;
FLEXCAN_0.CTRL.B.PROPSEG = 4U;
FLEXCAN_0.CTRL.B.PRESDIV = 9U;
FLEXCAN_0.CTRL.B.RJW = 1U;
FLEXCAN_0.CTRL.B.SMP = 0b0;
FLEXCAN_0.CTRL.B.LBUF = 0b1; /* Lowest buffer first */
FLEXCAN_0.CTRL.B.TWRN_MSK = 0b1;
FLEXCAN_0.CTRL.B.RWRN_MSK = 0b1;
FLEXCAN_0.CTRL.B.BOFF_MSK = 0b1;
FLEXCAN_0.CTRL.B.ERR_MSK = 0b1;
FLEXCAN_0.CTRL.B.LOM = 0b0; /* listen-only */
FLEXCAN_0.CTRL.B.LPB = 0b0; /* loop back */
FLEXCAN_0.CTRL.B.TSYN = 0b0;
FLEXCAN_0.MCR.B.FRZ = 0U;
while (1 == FLEXCAN_0.MCR.B.FRZ_ACK)
;/* leave freeze mode */
/* IRQ setting for TX buffers */
FLEXCAN_0.IMASK1.R = 0xFFFF0000UL;
/* Clear interrupt flags with ones */
FLEXCAN_0.IFLAG1.R = 0xFFFFFFFUL;
/* Synchronize to CAN bus */
FLEXCAN_0.MCR.B.HALT = 0U;Transmit section:
/* clear IRQ flags with ones */
FLEXCAN_0.IFLAG1.R = 0xFFFFFFFUL;
/* Lock message buffer */
(void) FLEXCAN_0.MB[0].MB_CS.B.CODE;
/* clear data fields */
FLEXCAN_0.MB[buffer].MB_DATAL.R = 0U;
FLEXCAN_0.MB[buffer].MB_DATAH.R = 0U;
/* inactivate buffer */
FLEXCAN_0.MB[buffer].MB_CS.B.CODE = 0b1000;
FLEXCAN_0.MB[buffer].MB_ID.R = frame->id << 18U;
/* Fill in data...*/
FLEXCAN_0.MB[buffer].MB_CS.B.LENGTH = frame->dlc;
FLEXCAN_0.MB[buffer].MB_CS.B.IDE = 0U; /* standard id */
FLEXCAN_0.MB[buffer].MB_CS.B.RTR = 0U; /* data frame */
FLEXCAN_0.MB[buffer].MB_CS.B.SRR = 0U;
/* start transmission */
FLEXCAN_0.MB[buffer].MB_CS.B.CODE = 0b1100;EDIT:
I am getting directly after transmit with "buffer" set to a TXD buffer this signal on the bus:
(obviously CANoe is sending error frames)
I discovered when I do a non fitting initialization of message boxes but with a number less than the MAXMB value then I get this signal instantly after FLEXCAN_0.MCR.B.FRZ = 0U during init.
And I have the same problem with the examples delivered with SPCStudio.
With Loop-back activated there are no problems.
Thank you in advance!
Regards
Ben