Aeroflex Circuit Technology

SCDCT2500 REV A 6/12/98 Plainview NY (516) 694-6700

4

RCVCNTRL

O

Received Control Bar

Pulses low upon reception of a Control Frame in both Sink and Source modes.

RCVDTA

O

Received Data/Command Word Bar

Pulses low upon reception of a Data or Command word

ERR1, ERR2

O

Error Bit One and Error Bit Two

OVRFLOW

O

Overflow Error

"1" = Overflow occurred in the Received Data Latch. Data not read in time.

RSTERR

I

Reset Error Flags Bar (Internal Pullup)

A low pulse on this line resets the ERR1, ERR2 and OVRFLOW error flags.

POR

I

Power on Reset Bar

A Master reset. A low pulse on this line resets the internal sequences and error flags.

It does not reset the I/O Data latches.

WIOUT

I

Word Identifier Bit Out

The value on this line is latched during STR2 for the WI bit position in the word to be

transmitted. A "0" indicates a Data word and a "1" indicates a Command/Interrupt

word.

WIIN

O

Word Identifier Bit In

The WI bit of the received word is present on this line during RCVDTA and indicates

whether the word is a Data word or a Command/Interrupt word. The value is latched at

the first RCVDTA for an entire Burst Mode reception.

CMDOUT

I

Command Out

Third bit of the transmitted Control Frame.

DTAOUT

I

Data Out

Second bit of the transmitted Control Frame.

LDCNTRL

I

Load Control Frame Bar

This loads the status of CMDOUT, DTAOUT and BIT4OUT into the Control Frame to

be transmitted. Transmission will commence when the loading is completed. This

applies to both Sink and Source modes.

FIFOEN

I

FIFO Enable

Source Mode: When FIFOEN is held high ("1"), FIFORD’s (FIFO Read Bars) will be

generated when the input data latch is empty (RDYFORDTA = 1). During the FIFORD,

data presented to the parallel bus will be loaded into the input data latch and

transmitted when ready. In a non-burst (single word) condition, FIFOEN must be

removed before RDYFORDTA comes back. A positive pulse of 100 ns duration

satisfies this requirement.

Sink Mode: The parallel data bus goes active during RCVDTA and will hold for

approximately 25 ns after its rising edge. With a FIFO directly connected to the data

bus, RCVDTA can be used to load all received words into the FIFO. Gating RCVDTA

with WIIN selects only the data words for loading.

I/O FUNCTION LISTING (Continued)

NAME

I/O

DESCRIPTION

ERR1

ERR2

0

0

No Error

0

1

Bit Count Error in Received Data/Command word or Control Frame

1

0

Parity Error in Received Data

1

1

Sync Error in Received Data/Command word or Control Frame