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dseq_bs

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dseq_bs [2006/07/05 23:15] – created messdseq_bs [2006/12/12 12:10] (current) – mess
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 +====== Bankstick Routines ======
 +
 +This routines will load/save patterns from a bankstick module
 +
 +
 +We're using the writepage MIOS function because a write to the bankstick takes a long time
 +this way we can write 64bytes at once so only 4 eeprom accesses are necessary
 +
 +First versions of the firmware had a pattern size of 128bytes 
 +so a pattern could be saved with two calls to the writepage function
 +
 +Saving a pattern with 256bytes takes four page writes, this makes it impossible
 +to save the four pages after each other without affecting the sequencer timing. \\
 +To avoid this the pattern is written over four ticks. Each time the program cycles through
 +the main loop a block is written until the whole pattern is saved.
 +
 +Reading from a eeprom is a lot quicker so we can just call readpage for each block...
 +
 +
 +
 +Code from bankstick.c:
 +
 +<code>
 +/////////////////////////////////////////////////////////////////////////////
 +// This function initialises a pattern save
 +/////////////////////////////////////////////////////////////////////////////
 +void BS_SavePat (unsigned char pat_nr){
 + //only init block save if no other save is in progress
 + if (save_block_cnt < NR_BLOCK)
 + return;
 +
 + //each pattern contains 256 bytes
 + //so address = pat_nr*256
 + writeaddr = ((unsigned int)pat_nr) << 8;
 + save_block_cnt = 0;
 +}
 +/////////////////////////////////////////////////////////////////////////////
 +// This function saves a pattern block to a bankstick
 +/////////////////////////////////////////////////////////////////////////////
 +void BS_SaveBlock (){
 + unsigned char error = 0;
 + //check if something has to be saved
 + if (save_block_cnt < NR_BLOCK) {
 + //write block
 + error |= MIOS_BANKSTICK_WritePage(writeaddr, buffer + (save_block_cnt<<6));
 + //calculate address of next block
 + writeaddr += 0x40;
 + save_block_cnt++;
 +
 + if (error) {
 + MIOS_LCD_CursorSet(0xC0 + 0);
 + MIOS_LCD_PrintCString("error saving pattern");
 + MIOS_LCD_MessageStart(128);
 + //stop saving pattern
 + save_block_cnt = NR_BLOCK;
 + }
 + }
 +
 +}
 +
 +/////////////////////////////////////////////////////////////////////////////
 +// This function loads a pattern from a bankstick
 +/////////////////////////////////////////////////////////////////////////////
 +void BS_LoadPat (unsigned char pat_nr){
 + unsigned int readaddr;
 + unsigned char i;
 + //each pattern contains 256 bytes
 + //so address = pat_nr*256
 + readaddr = ((unsigned int)pat_nr) << 8;
 +
 + //load all values to bankstick
 + //(will be optimised in the future)
 + MIOS_BANKSTICK_ReadPage(readaddr + 0x00, buffer + 0x00);
 + MIOS_BANKSTICK_ReadPage(readaddr + 0x40, buffer + 0x40);
 + MIOS_BANKSTICK_ReadPage(readaddr + 0x80, buffer + 0x80);
 + MIOS_BANKSTICK_ReadPage(readaddr + 0xC0, buffer + 0xC0);
 +
 + MIOS_LCD_CursorSet(0xC0 + 0);
 + if (MIOS_BOX_STAT.BS_AVAILABLE) {
 + MIOS_LCD_PrintCString("load ok");
 + } else {
 + MIOS_LCD_PrintCString("load error");
 + }
 + MIOS_LCD_MessageStart(128);
 +}
 +
 +</code>
 +\\
 +back to [[DSEQ32]]