78 lines
3.1 KiB
C
78 lines
3.1 KiB
C
/* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/** library for enhanced USART communication (API)
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* @file usart_enhanced.h
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2018
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* @details the USART peripherals only support 8 or 9-bit word and even or odd parity (included in the data bits). The library adds support for 5 to 8-bit words, none/even/odd/mark/space parity (on top of the data bits)
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* @note since parity is handled in software, the parity error (PE) flag is unused and should be replaced by the value return by usart_enhanced_parity_error
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* @remark 9-bit raw communication is not supported since this is not common and can be done without this library
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*/
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#pragma once
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/** enhanced USART setting for the additional parity bit*/
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enum usart_enhanced_parity_t {
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/** no parity */
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USART_ENHANCED_PARITY_NONE,
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/** even parity
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* @note the number of 1's is even
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*/
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USART_ENHANCED_PARITY_EVEN,
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/** odd parity
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* @note the number of 1's is odd
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*/
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USART_ENHANCED_PARITY_ODD,
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/** mark parity
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* @note the parity bit is 1
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*/
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USART_ENHANCED_PARITY_MARK,
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/** space parity
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* @note the parity bit is 0
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*/
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USART_ENHANCED_PARITY_SPACE,
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};
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/** know if there is an even number of 1's in a integer
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* @note this look up table is only useful for up to 8-bit words, else use __builtin_parity
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* @remark a look-up is a lot faster than making the calculation and doesn't use a lot of (flash) memory
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*/
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extern const bool usart_enhanced_even_parity_lut[256];
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/** configure enhanced USART
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* @param[in] usart USART peripheral base address
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* @param[in] databits word size in bits (5 to 8)
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* @param[in] parity additional parity bit
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* @return if the input settings are valid and the configuration is successful
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*/
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bool usart_enhanced_config(uint32_t usart, uint8_t databits, enum usart_enhanced_parity_t parity);
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/** send data over the enhanced USART using the configuration
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* @param[in] usart USART peripheral base address
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* @param[in] data data to be sent
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* @note uses usart_send
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*/
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void usart_enhanced_send(uint32_t usart, uint8_t data);
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/** receive data over the enhanced USART using the configuration
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* @param[in] usart USART peripheral base address
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* @return data received
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* @note uses usart_recv
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*/
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uint8_t usart_enhanced_recv(uint32_t usart);
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/** get the parity status of the received data
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* @param[in] usart USART peripheral base address
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* @return if there is a parity error
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* @note the check only applies to the last data retrieved using usart_enhanced_recv
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*/
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bool usart_enhanced_parity_error(uint32_t usart);
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