can_bit_timings_core/
lib.rs

1#![no_std]
2/*
3 * Copyright (c) 2021, Pavel Pletenev
4 *
5 * This file is part of can_bit_timings project
6 *
7 * This Source Code Form is subject to the terms of the Mozilla Public
8 * License, v. 2.0. If a copy of the MPL was not distributed with this
9 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
10 */
11
12/// This struct holds parts of bit timing for CAN.
13/// Field descriptions quote descriptions from [this site](http://www.bittiming.can-wiki.info/).
14#[derive(Clone, Copy, Debug, PartialEq, PartialOrd)]
15pub struct CanBitTiming {
16    /// **bs1** = **PROP_SEG** + **PHASE_SEG1**
17    ///
18    /// **PROP_SEG** is programmable to be 1, 2,... 8 Time Quanta long. 
19    /// It is used to compensate for signal delays across the network.
20    ///
21    /// **PHASE_SEG1** is programmable to be 1,2, ... 8 Time Quanta long. 
22    /// It is used to compensate for edge phase errors and may be lengthened 
23    /// during resynchronization.
24    pub bs1: u8,
25
26    /// **bs2** = **PHASE_SEG2** (Seg 2) is the maximum of PHASE_SEG1 and 
27    /// the Information Processing Time long. It is also used to compensate edge 
28    /// phase errors and may be shortened during resynchronization. 
29    /// For this the minimum value of PHASE_SEG2 is the value of SJW.
30    /// Information Processing Time is less than or equal to 2 Time Quanta long.
31    pub bs2: u8,
32
33    /// Synchronization Jump Width
34    pub sjw: u8,
35
36    /// Prescaler value
37    pub prescaler: u16
38}
39
40
41impl CanBitTiming {
42    /// Converts [CanBitTiming] struct to a `u32` register
43    /// as used by bxcan module.
44    pub fn bxcan(&self) -> u32 {
45        (self.sjw as u32 - 1 ) << 24
46        | (self.bs1 as u32 - 1) << 16
47        | (self.bs2 as u32 - 1 ) << 20
48        | (self.prescaler as u32 -1 )
49    }
50
51    /// Outputs total time quanta used to clock a CAN bus module
52    pub fn total_time_quanta(&self) -> u16 {
53        self.bs1 as u16 + self.bs2 as u16 + self.sjw as u16
54    }
55}
can_bit_timings_core/lib.rs

can_bit_timings_core/
lib.rs
