Quote:
Originally Posted by katarakt
* Lots of 100nF 0805 X7R capacitors
|
There's enough pads to put 1, 2 or 3 decoupling caps for each DRAM chip. I'm not going to scientifically measure how many you need, but probably 2 per chip is plenty.
So populate C1, C2, C4, C5, C7, C8, C21, C22 with 100nF.
Quote:
Originally Posted by katarakt
The parts list for RTC:
U4: OKI M6242B (I got some second hand ones from AliExpress for $2)
Y1: 32.768KHz MC306 crystal
C10: 47K-100K 0805 resistor (yes a resistor!)
C13: 100nF 0805 capacitor
C12: >=2.2uF 10V 0805 tantalum or ceramic capacitor
R1, R2, R3: 10K 0805 resistor
R4, R5: 220-470 0805 resistor
D1: BAT721C or BAT54C diode
C14,C15: 22-27pF 0805 capacitor
Battery Holder: Some cheap ebay one.
Alternatively, get a RTC-62421/72421 and you can leave off Y1, C14, C15. It makes it simpler.
|
Ignore the eagle file, the above BOM is good. Even C10 as a resistor is right.