MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

2–1

REV 2

12/93

3Bit Scannable Registered

Bus Transceiver

The MC10E/100E337 is a 3-bit registered bus transceiver with scan.

The bus outputs (BUS0–BUS2) are specified for driving a 25

Ω bus; the

receive outputs (Q0 – Q2) are specified for 50

Ω. The bus outputs feature

a normal HIGH level (VOH) and a cutoff LOW level — when LOW, the

outputs go to – 2.0V and the output emitter-follower is “off”, presenting a

high impedance to the bus. The bus outputs also feature edge slow-down

capacitors.

Both drive and receive sides feature the same logic, including a loopback path to hold data. The HOLD/LOAD function is

controlled by Transmit Enable (TEN) and Receive Enable (REN) on the transmit and receive sides respectively, with a HIGH

selecting LOAD. Note that the implementation of the E337 Receive Enable differs from that of the E336.

A synchronous bus enable (SBUSEN) is provided for normal, non-scan operation. The asynchronous bus disable (ABUSDIS)

disables the bus immediately for scan mode.

The SYNCEN input is provided for flexibility when re-enabling the bus after disabling with ABUSDIS, allowing either

synchronous or asynchronous re-enabling. An alternative use is asynchronous-only operation with ABUSDIS, in which case

SYNCEN is tied LOW, or left open. SYNCEN is implemented as an overriding SET control (active-LOW) to the enable flip-flop.

Scan mode is selected by a HIGH at the SCAN input. Scan input data is shifted in through S_IN and output data appears at the

Q2 output.

All registers are clocked on the positive transition of CLK. Additional lead-frame grounding is provided through the Ground pins

(GND) which should be connected to 0V. The GND pins are not electrically connected to the chip.

PIN NAMES

Pin

Function

A0 – A2

Data Inputs A

B0 – B2

Data Inputs B

S-IN

Serial (Scan) Data Input

TEN, REN

HOLD/LOAD Controls

SCAN

Scan Control

ABUSDIS

Asynchronous Bus Disable

SBUSEN

Synchronous Bus Enable

SYNCEN

Synchronous Enable Control

CLK

Clock

BUS0 – BUS2

25

Ω Cutoff Bus Outputs

Q0 – Q2

Receive Data Outputs (Q2 serves as SCAN_OUT in scan mode)

MC10E337

MC100E337

3-BIT SCANNABLE

REGISTERED

BUS TRANSCEIVER

FN SUFFIX

PLASTIC PACKAGE

CASE 776-02