| Electronics > Beginners |
| tmm41256p-15 DRAM tester |
| (1/1) |
| Homer_79:
Here is the datasheet, for the tmm41256p-15 https://4donline.ihs.com/images/VipMasterIC/IC/TOSC/TOSCS32892/TOSCS32892-1.pdf I'm doing some work with DRAM, so I thought i'd start with something simple. This is basically what I want to build, but I thought I would start by understanding how the software works first. http://www.chronworks.com/DRAM/ http://www.chronworks.com/DRAM/memoryTest.ino I can follow the code through and it kind of makes sence. Its just an array of 512x512 bits. But how the decoding of the 9 bits is something im struggling with. // First write all Zeros to DRAM digitalWrite(DIN, LOW); for(col = 0 ; col < 512 ; col++) { for(row = 0 ; row < 512 ; row++) { PORTB = row & 0x3f; // Write out ROW address ---- Why set all 6 bits to 1's? PORTC = ((col & 0x1c0) >> 6) | blue; ---- what does this line do? I thought portc would start off at bits 0, not the upper 6 I'm just starting out with arduino, so forgive me learning curve. many thanks |
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