CT2579 datasheet(6/41 Pages) AEROFLEX

6 / 41 page

APPLICATION NOTE #108

Released 9/98

Multibus Mode:Write strobe for a data transfer

0 = Write data FROM the Subsystem TO the Device

1 = Tri-state the Data0-15 bus

RT Status Word Discrete Inputs

The following signals are inputs to set the appropriate bits in the RT Status word. All inputs are

sampled after the NVCR signal. These RT Status Word inputs should be latched by NVCR and

remain stable until the next NVCR signal. All the inputs listed below are active low. To set any of the

appropriate bits, the user must pull that input "low" ("0")

NME

Message Error, illegalizes message. Command will not be stored in Command /

Status memory and no transfers to / from main RAM will take place. No data will be

transmitted following the status.

NTF

Sets the Terminal Flag bit

NSR

Sets the Service Request bit

NBUSY

Sets the Subsystem Busy bit

NSSFLAG

Sets the Subsystem Flag bit

NDBCA

Sets the Dynamic Bus Control Accept bit in response to the Mode Code “Dynamic

Bus Control Request”

RT Discrete Signals

BCST

Output high indicates command received was a broadcast. Signal will remain high until next

command is received

"1" = Broadcast Command was received

MCDET

Output high indicates command received was a mode command. Signal will remain high until

next command is received

"1" = Mode Code Command was received

NCMDSTRB This signal indicates that a completely validated message has been received for

standard subaddress data activity. Mode commands with or without data will not

generate this signal. The NCMDSTRB signal is 8.5 uS long and is an indication that a

DMA burst will initiate at the end of NCMDSTRB to transfer words between the 32

word data memory and the internal main RAM. All subsystem read / writes to the

main RAM that have been acknowledged (NACK = “0") before NCMDSTRB has

begun must now be completed within 8.5 uS. All subsystem read / write requests to

the main RAM initiated after NCMDSTRB has begun will be held off (no

acknowledge) until the DMA cycle has been completed. The length of the DMA cycle

is dependant on the number of words to DMA into RAM. Access to the 32 word BTL

memory is still possible during the DMA cycle by the subsystem. However, transfers

between the BTL memory and the main RAM will be locked out.

NDBC

Active low indicates that the command received by the Remote Terminal was mode

code Dynamic Bus Control. Signal will remain low until next command is received.

CT2579 датащи(PDF) 6 Page - Aeroflex Circuit Technology

CT2579 датащи(HTML) 6 Page - Aeroflex Circuit Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

датащи скачать

ссылки URL