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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:
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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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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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9 |
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10 | // FIXME there are two USARTs in this case and we should be able to drive either
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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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22 | #endif
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23 |
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24 | void USARTInit()
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25 | {
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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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44 | #elif defined __AVR_ATmega128__
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45 | UCSR0C = (2 << UCSZ0) | (2 << UPM0) ; /* 7 bits + even parity.
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46 | TODO make this configurable. */
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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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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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59 | while(!(UCSR0A & (1<<UDRE0)))
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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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73 | while(!(UCSR0A & (1<<RXC0)))
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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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81 | return UDR0;
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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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