Aeroflex Circuit Technology

23

SCDCT2553 REV B 8/6/99 Plainview NY (516) 694-6700

TRANSMIT VECTOR WORD (10000)

MESSAGE SEQUENCE - TRANSMIT VECTOR WORD * STATUS VECTOR WORD

The CT2553 transmits a status word followed by a vector word. The contents of the vector word (from the subsystem) are enabled onto

DBO-DB15 with BUSREQ after the command transfer (same as data word in a normal transmit command).

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW) High Word Count (BIT Word).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error, Low Word Count (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode Code, T/R

Error, Low Word Count (BIT Word).

5. Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode code, (BIT Word).

SYNCHRONIZE WITH DATA WORD (10001)

MESSAGE SEQUENCE - SYNCHRONIZE DATA WORD * STATUS

The data word received following the command word is transferred to the subsystem. The status register is then enabled and its contents

transferred onto the data bus and transmitted. If the command was broadcast, the broadcast received bit is set and status transmission is

suppressed.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Not Followed by Data Word. No status response. Bits set: message error (SW), Low Word Count (BIT Word).

3. Command followed by too many Data Words. No status response. Bits set: message error (SW), High Word Count (BIT word).

4. Command T/R bit Set to One. No status response. Bits set: message error (SW), T/R Error, High Word Count (BIT Word).

5. Command, T/R bit Set to One and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), High

Word Count, T/R Error (BIT Word).

TRANSMIT LAST COMMAND (10010)

MESSAGE SEQUENCE = TRANSMIT LAST COMMAND * STATUS LAST COMMAND

The status and BIT word registers are not altered by this command. The SW contains the status from the previous command. The data

word transmitted contains the previous valid command (providing it was not another TRANSMIT LAST COMMAND).

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error, Low Word Count (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, (SW), Illegal Mode Code T/R Error (BIT Word).

5. Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode Code (BIT Word).

TRANSMIT BIT WORD (10011)

MESSAGE SEQUENCE - TRANSMIT BIT WORD * STATUS BIT WORD

The CT2553 transmits a status word followed by the BIT word . When activated, BITEN allows the subsystem to latch the BIT word on the

parallel data bus. The BIT word is not altered by this command; however, the next SW will reflect errors in this transmission.

ERROR CONDITIONS

1. Invalid Command. No response, command ignored.

2. Command Followed by Data Word. No status response. Bits set: message error (SW).

3. T/R bit Set to Zero. No status response. Bits set: message error (SW), T/R Error, Low Word Count (BIT Word).

4. Zero T/R bit and Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode Code, T/R

Error, Low Word Count (BIT Word).

5. Broadcast Address. No status response. Bits set: message error, broadcast received (SW), Illegal Mode code, (BIT Word).

Table 6 – Mode Codes (continued)