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HAL_ChibiOS: fixed CANFD timings (again!) 

the timing table was not correct, thanks to APD for pointing this out.

This is recalculated from
https://www.kvaser.com/support/calculators/can-fd-bit-timing-calculator,
with transmitter timing delay compensation added and tested with Salae
captures to ensure we are getting the right bit rates
This commit is contained in:
Andrew Tridgell 2024-02-05 12:44:44 +11:00
parent 52409d6765
commit e8b4010899
1 changed files with 11 additions and 6 deletions
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17
libraries/AP_HAL_ChibiOS/CANFDIface.cpp
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@ -323,6 +323,7 @@ bool CANIface::computeTimings(const uint32_t target_bitrate, Timings& out_timing
/*
table driven timings for CANFD
These timings are from https://www.kvaser.com/support/calculators/can-fd-bit-timing-calculator
*/
bool CANIface::computeFDTimings(const uint32_t target_bitrate, Timings& out_timings) const
{
@ -334,11 +335,11 @@ bool CANIface::computeFDTimings(const uint32_t target_bitrate, Timings& out_timi
uint8_t sjw;
uint8_t sample_point_pct;
} CANFD_timings[] {
{ 1, 5, 15, 6, 6, 75},
{ 2, 3, 15, 6, 6, 75},
{ 4, 2, 15, 6, 6, 75},
{ 5, 2, 12, 5, 5, 75},
{ 8, 2, 8, 3, 3, 80},
{ 1, 4, 14, 5, 5, 75},
{ 2, 2, 14, 5, 5, 75},
{ 4, 1, 14, 5, 5, 75},
{ 5, 1, 11, 4, 4, 75},
{ 8, 1, 6, 3, 3, 70},
};
for (const auto &t : CANFD_timings) {
if (t.bitrate_mbaud*1000U*1000U == target_bitrate) {
@ -719,7 +720,11 @@ bool CANIface::init(const uint32_t bitrate, const uint32_t fdbitrate, const Oper
can_->DBTP = (((fdtimings.bs1-1) << FDCAN_DBTP_DTSEG1_Pos) |
((fdtimings.bs2-1) << FDCAN_DBTP_DTSEG2_Pos) |
((fdtimings.prescaler-1) << FDCAN_DBTP_DBRP_Pos) |
((fdtimings.sjw-1) << FDCAN_DBTP_DSJW_Pos));
((fdtimings.sjw-1) << FDCAN_DBTP_DSJW_Pos)) |
FDCAN_DBTP_TDC;
// use a transmitter delay compensation offset of 10, suitable
// for MCP2557FD transceiver with delay of 120ns
can_->TDCR = 10<<FDCAN_TDCR_TDCO_Pos;
}
//RX Config