mitsubishi - Al Kossow's Bitsavers

MITSUBISHI MICROCOMPUTERSMSL8243PINPUT/OUTPUT EXPANDERExampleTo use 20mA sinking capability at port 7, find the effects onthe sinking capabilities of the other liD lines.Assume the M5L8243P is driving loads as shown below.3 lines: -20mA (VOL = 1.0V max, port 7 only)4 lines: -4mA (VOL = O.45V max)9l!nes: -1.6mA (VOL = O.45V max)Is this within the allowable limit?k IOL = (20mA X 3) + (4mA X 4) + (1.6mA X 9) =90.4mAFrom the curve we see that with respect to IOL = 4mA, IOLis 93mA (Point B) and that the above load of 90.4mA is withinthe limit of 93mA.Note: The sinking current of ports 4 -- 7 must not exceed30mA regardless of the value of VOL.Flg.2Expansion interface exampleII• MITSUBISHI.... ELECTRIC6-31