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Looks interesting,
I need something along the lines of a battery charger, constant current while stepping down the voltage. Microchip/Atmel have app notes on the topic; i was interested to see if anybody implemented something similar and how reliable/safe the firmware was.
1) powerin--------a-------schottky--------b--------mcu
2) c-----charger---d----schottky-------e
3) gnd-------supercap-------f
Connect:
c to a
e to b
f to d
if you do this you wont have problems
the charger can be a mosfet+current limiting resistor
look at app notes at www.cap-xx.com in the...
if you use a supercap:
dV=I*ESR+I*dt/C
trivial example:
dV=0.5V (allowable drop in voltage from vcc)
I=0.1A (current needed)
ESR supercap=0.080Ohm
C supercap=1F
0.5=0.008+0.1*dt
dt=4.92 seconds....that's enough time to erase+write 8K of flash
-if you place the cap in parallel with the...
fooling usb advanced
is there any way to fool a usb host that it's still attached to a usb hub given that Vbus+Gnd are attached, and milisecond disconnects on D+,D-? How about a pull-up on D+ on the host side
For the capacitor i would use something with a very low ESR you wont get much power out of it otherwise
You can also provide power to your whole assembly mcu included if you use a supercapacitor; they have esr in the range of tens of milliohms. Then all you need is a fet to charge it and a...
key pad interfacing program for arm at91sam7s256
write 3 routines:
1) getRowValue
- drive columns low sequentially
- for each column driven low look for 2 rows (max) being low (this way you can implement chording)
2) getKey
- this calls routine 1 and returns max 2rows 2 columns = 2 keys...
best convert composite
TVP5150 from TI accepts composite and svhs and spits out 8 bit 4:2:2 YcbCr and discrete syncs; it's cheap; and all you need to do is a 3x3 matrix multiplication to get RGB; xilinx has app note
majnoon : i prefer to use pads and create a single gerber....it's safer; thanks though
Beepster :
What i forgot to mention probably the most important feat. is that my boards all have mixed gnd/power planes with power=7 different plane areas and 2 different grounds, the planes do not copy and...
on screen display
hi all
any suggestions/papers/pointers/tutorials on how to go about implementing an on screen display for a lcd fpga (xilinx vhdl) application?
cheers
radu
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