DESCRIPTION
The M54HC/74HC670 is a 4 x 4 Register File organized as four words by four bits. Separate read and write inputs, both address and enable, allow simultaneous read and write operation. The 3-state outputs make it possible to connect up to 128 outputs to increase the word capacity up to 512 words. Any number of these devices can be operated in parallel to generate an n-bit length. All inputs are equipped with protection circuits against static discharge and transient excess voltage. October 1992 NC = No Internal Connection 1/12 M54/M74HC670 WRITE FUNCTION TABLE WRITE INPUTS WB L L H H X WA L H L H X WE L L L L H 0 Q=D Q0 Q0 Q0 Q0 WORDS 1 Q0 Q=D Q0 Q0 Q0 2 Q0 Q0 3 Q0 Q0 READ FUNCTION TABLE READ INPUTS RB L L H H X RA L H L H X RE L L L L H OUTPUTS Q0 Q1 Q2 Q3 W0B1 W0B2 W0B3 W0B4 W1B1 W1B2 W1B3 W1B4 W2B1 W2B2 W2B3 W2B4 W3B1 W3B2 W3B3 W3B4 Z Z Z Z Q=D Q0 Q0 Q=D Q0 Q0 Notes: 1 *: DON’T CARE Z: HIGH IMPEDANCE 2 (Q = D) = THE FOUR SELECT INTERNAL FLIP FLOP OUTPUTS WILL ASSUME THE STATES APPLIED TO THE FOUR EXTERNAL DATA INPUTS.
STMicroelectronics
