mirror of https://github.com/ARMmbed/mbed-os.git
[M487] Support CAN feature
cyliangtw
ccli8
parent
95e0bc094a
commit
d32607294f
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@ -62,7 +62,10 @@ extern void CAN_EnterTestMode(CAN_T *tCAN, uint8_t u8TestMask);
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// Reset this module
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SYS_ResetModule(modinit->rsetidx);
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NVIC_DisableIRQ(CAN0_IRQn);
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NVIC_DisableIRQ(CAN1_IRQn);
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// Enable IP clock
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CLK_EnableModuleClock(modinit->clkidx);
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@ -29,6 +29,15 @@ static uint8_t gu8LockCanIf[1][2] = {0}; // The chip only has one CAN.
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#define RETRY_COUNTS (0x10000000)
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#define TSEG1_MIN 2
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#define TSEG1_MAX 16
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#define TSEG2_MIN 1
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#define TSEG2_MAX 8
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#define BRP_MIN 1
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#define BRP_MAX 1024 /* 6-bit BRP field + 4-bit BRPE field*/
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#define SJW_MAX 4
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#define BRP_INC 1
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//#define DEBUG_PRINTF printf
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#define DEBUG_PRINTF(...)
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@ -546,8 +555,22 @@ int32_t CAN_ReadMsgObj(CAN_T *tCAN, uint8_t u8MsgObj, uint8_t u8Release, STR_CAN
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return TRUE;
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}
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/// @endcond HIDDEN_SYMBOLS
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static int can_update_spt(int sampl_pt, int tseg, int *tseg1, int *tseg2)
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{
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*tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
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if (*tseg2 < TSEG2_MIN)
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*tseg2 = TSEG2_MIN;
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if (*tseg2 > TSEG2_MAX)
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*tseg2 = TSEG2_MAX;
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*tseg1 = tseg - *tseg2;
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if (*tseg1 > TSEG1_MAX) {
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*tseg1 = TSEG1_MAX;
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*tseg2 = tseg - *tseg1;
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}
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return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
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}
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/// @endcond HIDDEN_SYMBOLS
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/**
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* @brief Set bus baud-rate.
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@ -561,14 +584,17 @@ int32_t CAN_ReadMsgObj(CAN_T *tCAN, uint8_t u8MsgObj, uint8_t u8Release, STR_CAN
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*/
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uint32_t CAN_SetBaudRate(CAN_T *tCAN, uint32_t u32BaudRate)
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{
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uint8_t u8Tseg1, u8Tseg2;
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uint32_t u32Brp;
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uint32_t u32Value;
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uint32_t u32PCLK_DIV = 1;
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long rate;
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long best_error = 1000000000, error = 0;
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int best_tseg = 0, best_brp = 0, brp = 0;
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int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
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int spt_error = 1000, spt = 0, sampl_pt;
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uint64_t clock_freq = 0, u32PCLK_DIV = 1;
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uint32_t sjw = 1;
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CAN_EnterInitMode(tCAN, 0);
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SystemCoreClockUpdate();
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SystemCoreClockUpdate();
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if(tCAN == CAN0) {
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if(CLK->CLKSEL0 & (1 << 6))
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u32PCLK_DIV = 2;
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@ -577,56 +603,77 @@ uint32_t CAN_SetBaudRate(CAN_T *tCAN, uint32_t u32BaudRate)
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u32PCLK_DIV = 2;
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}
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u32Value = SystemCoreClock / u32BaudRate / u32PCLK_DIV;
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clock_freq = SystemCoreClock / u32PCLK_DIV;
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#if 0
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u8Tseg1 = 2;
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u8Tseg2 = 1;
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while(1) {
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if(((u32Value % (u8Tseg1 + u8Tseg2 + 3)) == 0))
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break;
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if(u8Tseg1 < 7)
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u8Tseg2++;
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if(u32BaudRate >= 1000000)
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u32BaudRate = 1000000;
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if((u32Value % (u8Tseg1 + u8Tseg2 + 3)) == 0)
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break;
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if(u8Tseg1 < 15)
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u8Tseg1++;
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else {
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u8Tseg1 = 2;
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u8Tseg2 = 1;
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break;
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/* Use CIA recommended sample points */
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if (u32BaudRate > 800000)
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sampl_pt = 750;
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else if (u32BaudRate > 500000)
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sampl_pt = 800;
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else
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sampl_pt = 875;
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/* tseg even = round down, odd = round up */
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for (tseg = (TSEG1_MAX + TSEG2_MAX) * 2 + 1; tseg >= (TSEG1_MIN + TSEG2_MIN) * 2; tseg--) {
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tsegall = 1 + tseg / 2;
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/* Compute all possible tseg choices (tseg=tseg1+tseg2) */
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brp = clock_freq / (tsegall * u32BaudRate) + tseg % 2;
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/* chose brp step which is possible in system */
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brp = (brp / BRP_INC) * BRP_INC;
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if ((brp < BRP_MIN) || (brp > BRP_MAX))
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continue;
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rate = clock_freq / (brp * tsegall);
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error = u32BaudRate - rate;
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/* tseg brp biterror */
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if (error < 0)
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error = -error;
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if (error > best_error)
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continue;
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best_error = error;
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if (error == 0) {
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spt = can_update_spt(sampl_pt, tseg / 2, &tseg1, &tseg2);
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error = sampl_pt - spt;
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if (error < 0)
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error = -error;
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if (error > spt_error)
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continue;
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spt_error = error;
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}
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}
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#else
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best_tseg = tseg / 2;
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best_brp = brp;
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/* Fix for most standard baud rates, include 125K */
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u8Tseg1 = 3;
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u8Tseg2 = 2;
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while(1) {
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if(((u32Value % (u8Tseg1 + u8Tseg2 + 3)) == 0) | (u8Tseg1 >= 15))
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if (error == 0)
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break;
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u8Tseg1++;
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if((u32Value % (u8Tseg1 + u8Tseg2 + 3)) == 0)
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break;
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if(u8Tseg2 < 7)
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u8Tseg2++;
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}
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#endif
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u32Brp = SystemCoreClock / (u32BaudRate) / (u8Tseg1 + u8Tseg2 + 3) - 1;
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u32Value = ((uint32_t)u8Tseg2 << CAN_BTIME_TSEG2_Pos) | ((uint32_t)u8Tseg1 << CAN_BTIME_TSEG1_Pos) |
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(u32Brp & CAN_BTIME_BRP_Msk) | (tCAN->BTIME & CAN_BTIME_SJW_Msk);
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tCAN->BTIME = u32Value;
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tCAN->BRPE = (u32Brp >> 6) & 0x0F;
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spt = can_update_spt(sampl_pt, best_tseg, &tseg1, &tseg2);
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/* check for sjw user settings */
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/* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
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if (sjw > SJW_MAX)
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sjw = SJW_MAX;
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/* bt->sjw must not be higher than tseg2 */
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if (tseg2 < sjw)
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sjw = tseg2;
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/* real bit-rate */
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u32BaudRate = clock_freq / (best_brp * (tseg1 + tseg2 + 1));
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tCAN->BTIME = ((uint32_t)(tseg2 - 1) << CAN_BTIME_TSEG2_Pos) | ((uint32_t)(tseg1 - 1) << CAN_BTIME_TSEG1_Pos) |
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((best_brp - 1) & CAN_BTIME_BRP_Msk) | (sjw << CAN_BTIME_SJW_Pos);
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tCAN->BRPE = ((best_brp - 1) >> 6) & 0x0F;
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printf("\n bitrate = %d \n", CAN_GetCANBitRate(tCAN));
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CAN_LeaveInitMode(tCAN);
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return (CAN_GetCANBitRate(tCAN));
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return u32BaudRate;
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}
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/**
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