CT2577 Datasheet, PDF (3/41 Pages) Aeroflex Circuit Technology – APPLICATION NOTE 108

Signal Descriptions
MIL-STD-1553 Bus Interface Signals
Data0(Bus) Connect to positive side of the external databus transformer for Bus 0
Ndata0(Bus) Connect to negative side of the external databus transformer for Bus 0
Data1(Bus) Connect to positive side of the external databus transformer for Bus 1
Ndata1(Bus) Connect to negative side of the external databus transformer for Bus 1
Hard Wired Interface Signals
AddrA-E
Remote Terminal address inputs for the unit. ADDR A is the least significant bit and
ADDR E is the most significant bit. RT Address inputs for the unit. AddrA is the LSB,
AddrE is the MSB.
AddrP
Parity Bit for the RT Address inputs. AddrP must be set to ODD parity
MACAIR
This signal sets the unit to respond with a status word within 4 uS (dead bus time)
while in Remote Terminal mode. Subaddress 1F is also enabled to be a valid
subaddress for data.
Normally subaddress 00 and 1F are reserved for mode codes.
“1" = 4 uS dead bus response time, subaddress 1F used for data.
“0" = 12 uS response time, subaddress 1F used for mode codes.
NBIT16
Select 8 or 16 bit subsystem data interface. In 8 bit mode only the lower 8 bits of the
databus (DATA 0-7) are used for all data transfers. If left open circuit the device will
default to 16 bit mode.
"0" = 16 Bit Mode
"1" = 8 Bit Mode
VME
Select VME or MULTIBUS subsystem interface. If left open circuit the device will
default to VME mode.
"0" = Multibus Mode
"1" = VME Mode
*WRAPEN
Select Remote Terminal wrap around to subaddress 1E. For this test to work correctly
theunit must be in RT mode. The Bus Controller sends data to subaddress 1E which
remains in the data buffer memory and is available to be sent back on the very next
command by the Bus Controller. The data in the data buffer memory in this mode
does not get transferred to the main RAM. If the very next command is not a transmit
command to subaddress 1E, the data buffer memory is flushed and will respond
normally to the next set of commands. If the wrap around test is enabled, data to
subaddress 1E must be transferred in the correct sequence.
"0" = Normal Mode
"1" = Wrap Around Mode
MIL-STD-1760 Signals
NENCHK Enables / Disables the internal hardware checksum generation and validation for both
Remote Terminal and Bus Controller. When enabled, the circuitry will check all
APPLICATION NOTE #108
3
Released 9/98