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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 29 | jimmy | 1 | /****************************************************************************** |
| 2 | * Copyright (C) 2005 Martin THOMAS, Kaiserslautern, Germany |
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| 3 | * <eversmith@heizung-thomas.de> |
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| 4 | * http://www.siwawi.arubi.uni-kl.de/avr_projects |
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| 5 | ***************************************************************************** |
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| 6 | * |
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| 7 | * File : spi.c |
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| 8 | * Version : 0.9 |
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| 9 | * |
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| 10 | * Summary : AVR SPI driver |
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| 11 | * |
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| 12 | *****************************************************************************/ |
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| 13 | |||
| 14 | #include <avr/io.h> |
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| 15 | #include "spi.h" |
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| 16 | |||
| 17 | #define SPIDONTCARE (0x00) |
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| 18 | |||
| 19 | /* init as SPI-Master */ |
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| 20 | void spi_init(void) |
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| 21 | { |
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| 22 | // SCK, SS!!, MOSI as outputs |
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| 23 | SPIDDR |= (1<<SPISCK)|(1<<SPISS)|(1<<SPIMOSI); |
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| 24 | // MISO as input |
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| 25 | SPIDDR &= ~(1<<SPIMISO); // cbi(SPIDDR,SPIMISO); |
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| 26 | // INIT interface, Master, set clock rate fck/128 TODO: check prescaler |
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| 27 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0)|(1<<SPR1); |
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| 28 | } |
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| 29 | |||
| 30 | uint8_t spi_readwrite(uint8_t data) |
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| 31 | { |
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| 32 | // set data to send into SPI data register |
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| 33 | SPDR = data; |
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| 34 | // Wait for transmission complete |
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| 35 | while(!(SPSR & (1<<SPIF))); |
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| 36 | // return data read from SPI |
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| 37 | return SPDR; |
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| 38 | } |
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| 39 | |||
| 40 | uint8_t spi_read(void) |
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| 41 | { |
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| 42 | return spi_readwrite(SPIDONTCARE); |
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| 43 | } |