Crates.io | smbus-pec |
lib.rs | smbus-pec |
version | 1.0.1 |
source | src |
created_at | 2020-08-09 09:35:36.027832 |
updated_at | 2021-05-23 21:11:01.110099 |
description | Minimal portable implementation of SMBus Packet Error Code calculation algorithm. |
homepage | https://github.com/eldruin/smbus-pec-rs |
repository | https://github.com/eldruin/smbus-pec-rs |
max_upload_size | |
id | 274586 |
size | 48,634 |
This is a portable minimal implementation of the System Management Bus (SMBus)
Packet Error Code calculation algorithm intended for use in no_std
.
SMBus 1.1 and later defines an optional Packet Error Checking mode. When used, an extra byte is appended to all transmissions containing a Packet Error Code (PEC).
The PEC is calculated over the whole transmission including address and read/write bit.
The polynomial used is x^8 + x^2 + x + 1
, which corresponds to CRC-8-ATM HEC
initialized to zero.
There is a number of crates implementing CRC algorithms but their intention is to be configurable, generic, use acceleration via SIMD instructions, etc.
This crate provides a portable and non-configurable implementation of exactly one algorithm: The one used for SMBus PEC (optionally using a pre-calculated lookup table).
This should allow the compiler to make good optimizations and allows for use of the algorithm in any target architecture with minimal code bloat.
This makes this crate specially well suited for use in no_std
environments.
A faster version of the algorithm is provided through the use of a pre-calculated
lookup table. This can be enabled through the lookup-table
feature.
With this feature enabled a table of 256 pre-calculated u8
values will be included
which avoids bit-by-bit calculation at the cost of the space needed to store it.
use smbus_pec::pec;
const ADDRESS: u8 = 0x5A;
const REGISTER: u8 = 0x06;
fn main() {
let pec_write = pec(&[ADDRESS << 1, REGISTER, 0xAB, 0xCD]);
println!("PEC: {}", pec_write); // prints 95
let data = [ADDRESS << 1, REGISTER, (ADDRESS << 1) + 1, 38, 58];
let pec_write_read = pec(&data);
println!("PEC: {}", pec_write_read); // prints 102
}
For questions, issues, feature requests, other changes, or just feedback, please file an issue in the github project.
Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.