main
Last change
on this file since e5dd493 was e5dd493, checked in by Adrien Destugues <pulkomandy@…>, 5 years ago |
usart: some cleanups.
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File size:
1.7 KB
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[b82c7b3] | 1 | /* AVR USART acces functions - stolen from Extreme Electronics */
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| 2 |
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| 3 | #include <avr/io.h>
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| 4 | #include <inttypes.h>
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| 5 |
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[cd3a9ac] | 6 | #ifndef BAUD
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| 7 | #error You must define BAUD to use libuart.
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| 8 | #endif
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[b82c7b3] | 9 |
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[6390cc3] | 10 | // FIXME there are two USARTs in this case and we should be able to drive either
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[e5dd493] | 11 |
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| 12 | // Compatibility for devices with single USART only
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| 13 | #ifdef __AVR_ATmega8__
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| 14 | #define UBRR0H UBRRH
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| 15 | #define UBRR0L UBRRL
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| 16 | #define UCSR0A UCSRA
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| 17 | #define UCSR0C UCSRC
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| 18 | #define UCSR0B UCSRB
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| 19 | #define UDR0 UDR
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| 20 | #define UDRE0 UDRE
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| 21 | #define RXC0 RXC
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[6390cc3] | 22 | #endif
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| 23 |
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[cd3a9ac] | 24 | void USARTInit()
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[b82c7b3] | 25 | {
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[cd3a9ac] | 26 | //Set Baud rate
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| 27 | #include <util/setbaud.h>
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| 28 | UBRRH = UBRRH_VALUE;
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| 29 | UBRRL = UBRRL_VALUE;
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| 30 | #if USE_2X
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| 31 | UCSRA |= (1 << U2X);
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| 32 | #else
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| 33 | UCSRA &= ~(1 << U2X);
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| 34 | #endif
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| 35 |
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| 36 | /*Set Frame Format
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| 37 | >> Asynchronous mode
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| 38 | >> No Parity
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| 39 | >> 1 StopBit
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| 40 | >> char size 8
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| 41 | */
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| 42 | #ifdef __AVR_ATtiny2313__
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| 43 | UCSRC = (1 << UCSZ1) | (1 << UCSZ0);
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[6390cc3] | 44 | #elif defined __AVR_ATmega128__
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[6c47e45] | 45 | UCSR0C = (2 << UCSZ0) | (2 << UPM0) ; /* 7 bits + even parity.
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| 46 | TODO make this configurable. */
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[cd3a9ac] | 47 | #else
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| 48 | UCSRC = (1 << URSEL) | (3 << UCSZ0);
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| 49 | #endif
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| 50 |
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| 51 | //Enable The receiver and transmitter
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| 52 | UCSRB = (1 << RXEN) | (1 << TXEN);
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[b82c7b3] | 53 | }
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| 54 |
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| 55 |
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| 56 | void USARTWriteChar(char data)
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| 57 | {
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| 58 | //Wait untill the transmitter is ready
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[6c47e45] | 59 | while(!(UCSR0A & (1<<UDRE0)))
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[b82c7b3] | 60 | {
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| 61 | //Do nothing
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| 62 | }
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| 63 |
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| 64 | //Now write the data to USART buffer
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| 65 |
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| 66 | UDR=data;
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| 67 | }
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| 68 |
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| 69 |
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| 70 | char USARTReadChar()
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| 71 | {
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| 72 | //Wait untill a data is available
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[6c47e45] | 73 | while(!(UCSR0A & (1<<RXC0)))
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[b82c7b3] | 74 | {
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| 75 | //Do nothing
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| 76 | }
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| 77 |
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| 78 | //Now USART has got data from host
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| 79 | //and is available is buffer
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| 80 |
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[6c47e45] | 81 | return UDR0;
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[b82c7b3] | 82 | }
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| 83 |
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| 84 |
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| 85 | void USARTWriteHex(unsigned char i)
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| 86 | {
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| 87 | unsigned char k = i>>4;
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| 88 | if (k <=9) k+='0';
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| 89 | else k+=('A'-10);
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| 90 |
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| 91 | USARTWriteChar(k);
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| 92 |
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| 93 | k = i&0xF;
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| 94 | if (k <=9) k+='0';
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| 95 | else k+=('A'-10);
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| 96 |
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| 97 | USARTWriteChar(k);
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| 98 | }
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