1 | RESET(MCP2515_CS);
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2 | spi_putc_async(0x90);
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3 | /* then prepare the SDCard block in the meantime */
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4 | mmc_prepareBlock();
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5 | /* and finish the async read from mcp*/
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6 | spi_getc_async();
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7 | /* now start reading the bytes */
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8 | spi_putc_async(0xff); /* sending the first byte request */
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9 |
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10 | /* byte 1 read from mcp + write to SD */
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11 | b=spi_getc_async(); /* waiting for the MCP-byte to return*/ \
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12 | spi_putc_async(0xff); /* sending the 2nd MCP-byte */ \
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13 | uspi_putc_async(b); /* push the byte to the SD */
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14 | *bp++=b; /* store the MCP-byte */ \
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15 |
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16 | #define HELPER() \
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17 | b=spi_getc_async(); /* waiting for the MCP-byte to return*/ \
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18 | spi_putc_async(0xff); /* sending the next MCP-byte request*/ \
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19 | uspi_getc_async(); /* waiting for the SD-byte to return*/ \
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20 | uspi_putc_async(b); /* push the byte to the SD */ \
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21 | *bp++=b; /* store the current MCP-byte */ \
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22 |
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23 | HELPER();/* byte 2 read from mcp + write to SD */
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24 | HELPER();/* byte 3 read from mcp + write to SD */
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25 | HELPER();/* byte 4 read from mcp + write to SD */
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26 | HELPER();/* byte 5 read from mcp + write to SD */
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27 | HELPER();/* byte 6 read from mcp + write to SD */
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28 | HELPER();/* byte 7 read from mcp + write to SD */
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29 | HELPER();/* byte 8 read from mcp + write to SD */
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30 | HELPER();/* byte 9 read from mcp + write to SD */
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31 | HELPER();/* byte 10 read from mcp + write to SD */
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32 | HELPER();/* byte 11 read from mcp + write to SD */
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33 | HELPER();/* byte 12 read from mcp + write to SD */
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34 |
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35 | /* byte 13 is special again */
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36 | b=spi_getc_async(); /* waiting for the MCP-byte to return*/
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37 | SET(MCP2515_CS); /* pulling byte high as early as possible */
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38 | uspi_getc_async(); /* waiting for the MCP-byte to return*/
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39 | uspi_putc_async(b); /* push the last byte to the SD */
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40 | *bp++=b; /* store the MCP-byte */
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41 |
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42 | /* read byte from SD */
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43 | uspi_getc_async();
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44 |
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45 | /* and we finish the block (triggering writes and such...)*/
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46 | mmc_finishBlock();
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47 |
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48 | ...
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49 |
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50 | void mmc_finishBlock() {
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51 | /* if not at the end of the 512 byte block, return */
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52 | if (condition_not_reached) {return;}
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53 | /* finish the block with 2 bytes of bogus checksums */
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54 | uspi_putc(0xde);
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55 | uspi_putc(0xad);
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56 | /* and wait for status */
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57 | uint8_t response=uspi_putc(0xff);
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58 | if (response!=0xff) { ; }
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59 | /* and wait for the finished writing block - low until then...*/
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60 | while(uspi_putc(0xaa)==0) ;
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61 | /* wait some time - for some reason the next happens too quick before the data is out*/
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62 | //_delay_us(1);
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63 | /* and now pull line high */
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64 | SET(MMC_CS);
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65 | }
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66 |
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67 | inline void spi_putc_async(uint8_t data) {
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68 | SPDR = data;
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69 | }
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70 |
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71 | inline uint8_t spi_getc_async(void) {
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72 | while( !( SPSR & (1<<SPIF) ) ) { ; }
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73 | return SPDR;
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74 | }
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75 |
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76 | inline void uspi_putc_async(uint8_t data) {
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77 | UDR0 = data;
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78 | }
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79 | inline uint8_t uspi_getc_async(void) {
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80 | while( !( UCSR0A & (1<<UDRE0) ) ) { ; }
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81 | return UDR0;
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82 | }
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