Hello, bit of a noob questions. May even belong in general electronics forum. Just needed to confirm I'm understanding the data sheet correctly, don't want any blue smoke !
The ATTiny has:
DC Current per I/O Pin:40.0 mA
DC Current VCC and GND: 200.0 mA
but in the fine print (notes 3 and 4) it says:
The sum of all IOL, for all ports, should not exceed 60 mA.
The sum of all IOH, for all ports, should not exceed 60 mA.
I'm not clear if this is a combined maximum (all source+all sink <=60ma) or is it (all source+all Sink<=120ma as long as each is less than 60ma). I guess you could also read it as maximums per PORT.
I'm multiplexing a bunch of LED's (as a learning exercise)setting the appropriate PORTBx high and PORTDx low.
Each LED is being sourced and sunk (?) through the chip.
ie. Assume my LED's draw 20ma ea. would that mean I can only turn one on at a time ? (1x20ma source+1x20ma sink) or can I do 3 (3x20ma source+3x20ma sink)
Further, the datasheet indicates that these maximums are for steady state conditions. Since I'm cycling through at 4Mhz does that mean I can push them closer to the chip max of 40ma/200ma ?
Thanks in advance.