4-72

FAST AND LS TTL DATA

MC74F160A

• MC74F162A

CP

D

NOTE:

This diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.

LOGIC DIAGRAM

DETAIL A

DETAIL A

DETAIL A

DETAIL A

P0

P1

P3

P2

CEP

CET

CP

Q0

Q1

Q2

Q3

MR (MC74F160A)

SR (MC74F162A)

Q0

Q0

TC

CP

CP D

Q

Q

CD

MC74F160A

MC74F162A

MC74F162A

ONLY

MC74F160A

ONLY

PE

FUNCTIONAL DESCRIPTION

The MC74F160A and MC74F162A count modulo-10 in the

BCD (8421) sequence. From state 9 (HLLH) they increment

to state 0 (LLLL). The clock inputs of all flip-flops are driven in

parallel through a clock buffer. Thus, all changes of the Q out-

puts (except due to Master Reset of the MC74F160A) occur

as a result of, and synchronous with, the LOW-to-HIGH transi-

tion of the CP input signal. The circuits have four fundamental

modes of operation, in order of precedence: asynchronous re-

set (MC74F160A), synchronous reset (MC74F162A), paral-

lel load, count-up and hold. Five control inputs — Master Re-

set

(MR,

MC74F160A),

Synchronous

Reset

(SR,

MC74F162A), Parallel Enable (PE), Count Enable Parallel

(CEP) and Count Enable Trickle (CET) — determine the mode

of operation, as shown in the Function Table. A LOW signal on

MR overrides all other inputs and asynchronously forces all

outputs LOW. A LOW signal on SR overrides counting and

parallel loading and allows all outputs to go LOW on the next

rising edge of CP. A LOW signal on PE overrides counting and

allows information on the Parallel Data (Pn) inputs to be

loaded into the flip-flops on the next rising edge of CP. With

PE and MR (MC74F160A) or SR (MC74F162A) HIGH, CEP

and CET permit counting when both are HIGH. Conversely, a

LOW signal on either CEP or CET inhibits counting.

The MC74F160A and MC74F162A use D-type edge-trig-

gered flip-flops and changing the SR, PE, CEP, and CET in-

puts when the CP is in either state does not cause errors, pro-

vided that the recommended setup and hold times, with

respect to the rising edge of CP, are observed.