资 源 简 介
The M54/74HC620/623 are high speed CMOSOCTAL BUS TRANSCEIVERS fabricated in silicongate C2MOS technology. They have the same highspeed performance of LSTTL combined with trueCMOS low power consumpTIon.These octal bus transceivers are designed for asynchronoustwo-way communicaTIon between databuses. The control funcTIon implementaTIon allowsmaximum flexibility in timing.These devices allow data transmission from the Abus to B bus or from the B to the A bus dependingupon the logic levels at the enable inputs (GBAandGAB). The enable inputs can be used to disable thedevice so that the buses are effectively isolated.The dual-enable configuration gives these devicesthe capability to storedata by simultaneous enablingof GBA and GAB.Each output reinforces its input in this transceiverconfiguration. Thus, when both control inputs areenabled and all other data sources to the two setsof bus lines are at high impedance, both sets of buslines (16 in all) will remain at their last states. The 8-bit codes appearing on the two sets of buses will beidentical for the ’HC623 or complementary for the’HC620. All inputs are equipped with protection circuitsagainst static discharge and transient excessvoltage.
