1 | unsigned char MMC_FLASH_Write (unsigned long address, unsigned char *scratch,
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2 | unsigned char *wdata, unsigned int length)
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3 | {
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4 | idata unsigned long flash_page_1; // First FLASH page address;
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5 | idata unsigned long flash_page_2; // Second FLASH page address;
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6 | idata unsigned int card_status; // Stores status returned from MMC;
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7 | idata unsigned int counter; // Byte counter used for writes to
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8 | // local copy of data block;
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9 | unsigned char xdata *index; // Pointer into local copy of data
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10 | // block, used during modification;
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11 | MMC_FLASH_Clear(address,scratch,length); // Clear desired write space;
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12 | if(length > 512) return 0; // Check for valid data length;
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13 | // Calculate first FLASH page address;
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14 | flash_page_1 = address & ~(PHYSICAL_BLOCK_SIZE-1);
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15 | // Calculate second FLASH page address;
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16 | flash_page_2 = (address+length-1) & ~(PHYSICAL_BLOCK_SIZE-1);
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17 | if(flash_page_1 == flash_page_2) // Handle single FLASH block condition;
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18 | {
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19 | // Set block length to default block
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20 | // size (512 bytes);
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21 | card_status = MMC_Command_Exec(SET_BLOCKLEN,
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22 | (unsigned long)PHYSICAL_BLOCK_SIZE,
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23 | EMPTY);
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24 | // Read data block;
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25 | card_status = MMC_Command_Exec(READ_SINGLE_BLOCK,flash_page_1,scratch);
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26 | index = (unsigned int)(address % PHYSICAL_BLOCK_SIZE + scratch);
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27 | counter = 0;
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28 | while(counter<length) // Modify write space in local copy;
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29 | {
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30 | *index++ = *wdata++;
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31 | counter++;
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32 | }
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33 | // Write modified block back to MMC;
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34 | card_status = MMC_Command_Exec(WRITE_BLOCK,flash_page_1,scratch);
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35 | }
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36 | else // Handle multiple FLASH block
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37 | { // condition;
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38 | // Set block length to default block
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39 | // size (512 bytes);
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40 | card_status = MMC_Command_Exec(SET_BLOCKLEN,
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41 | (unsigned long)PHYSICAL_BLOCK_SIZE,
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42 | EMPTY);
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43 | // Read first data block;
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44 | card_status = MMC_Command_Exec(READ_SINGLE_BLOCK,flash_page_1,scratch);
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45 | index = (unsigned int)(address % PHYSICAL_BLOCK_SIZE + scratch);
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46 | counter = (unsigned int)(flash_page_2 - address);
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47 | while(counter > 0) // Modify data in local copy of first
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48 | { // block;
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49 | *index++ = *wdata++;
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50 | counter--;
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51 | }
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52 | // Write local copy back to MMC;
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53 | card_status = MMC_Command_Exec(WRITE_BLOCK,flash_page_1,scratch);
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54 | // Read second data block;
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55 | card_status = MMC_Command_Exec(READ_SINGLE_BLOCK,flash_page_2,scratch);
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56 | @@@ index = scratch;
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57 | counter = (unsigned int)(length - (flash_page_2 - address));
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58 | while(counter > 0) // Modify data in local copy of second
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59 | { // block;
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60 | *index++ = *wdata++;
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61 | counter--;
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62 | }
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63 | // Write local copy back to MMC;
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64 | card_status = MMC_Command_Exec(WRITE_BLOCK,flash_page_2,scratch);
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65 | }
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66 | }
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