From 7c56be8a724e2b0647e5a6cbd55c7b0eb948206b Mon Sep 17 00:00:00 2001 From: Sebastian Muszytowski Date: Fri, 3 Jun 2016 15:48:16 +0200 Subject: initial commit of all data --- src/Hamming/Hamming.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 src/Hamming/Hamming.h (limited to 'src/Hamming/Hamming.h') diff --git a/src/Hamming/Hamming.h b/src/Hamming/Hamming.h new file mode 100644 index 0000000..7778a59 --- /dev/null +++ b/src/Hamming/Hamming.h @@ -0,0 +1,68 @@ +/* +Hamming Error-Correcting Code (ECC) +Optimized for avr-gcc 4.8.1 in Atmel AVR Studio 6.2 +August 12, 2014 + +You should include Hamming.c, Hamming.h, and only one of the other Hamming files in your project. +The other Hamming files implement the same methods in different ways, that may be better or worse for your needs. + +This was created for LoFi in the TheHackadayPrize contest. +http://hackaday.io/project/1552-LoFi + +Copyright 2014 David Cook +RobotRoom.com + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + +http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +*/ + +#ifndef _HAMMING_H +#define _HAMMING_H + +#ifndef _AVR_H +typedef unsigned char byte; +typedef unsigned char nibble; +#endif + +/**** These are needed to transmit and receive ****/ + +// Given a byte to transmit, this returns the parity as a nibble +nibble HammingCalculateParity128(byte value); + +// Given two bytes to transmit, this returns the parity +// as a byte with the lower nibble being for the first byte, +// and the upper nibble being for the second byte. +byte HammingCalculateParity2416(byte first, byte second); + + + +/**** These are needed only to receive ****/ + +// Given a pointer to a received byte and the received parity (as a lower nibble), +// this calculates what the parity should be and fixes the received value if needed. +// It returns the number of bits corrected: +// 0 means no errors +// 1 means one corrected error +// 3 means corrections not possible +byte HammingCorrect128(byte* value, nibble parity); + +// Given a pointer to a first value and a pointer to a second value and +// their combined given parity (lower nibble first parity, upper nibble second parity), +// this calculates what the parity should be and fixes the values if needed. +// It returns the number of bits corrected: +// 0 means no errors +// 1 means one corrected error +// 2 means two corrected errors +// 3 means corrections not possible +byte HammingCorrect2416(byte* first, byte* second, byte parity); + +#endif // _HAMMING_H -- cgit v1.2.3