Rainbow Electronics DS26503 - Manual (Page 20)

DS26503 T1/E1/J1 BITS Element
20 of 123
NAME TYPE FUNCTION
A0/E1TS I
Address Bus Bit A[0]/E1 Termination Select
A0: In nonmultiplexed bus operation (BIS[1:0] = 01), this pin serves as A[0].
In multiplexed bus operation (BIS[1:0] = 00), these pins are not used and
should be tied low.
E1TS: In Hardware Mode (BIS[1:0] = 11), selects the E1 internal termination
value (0 = 120
W, 1 = 75W).
BTS/HBE I
Bus Type Select/Transmit and Receive B8ZS/HDB3 Enable
BTS: Strap high to select Motorola bus timing; strap low to select Intel bus
timing. This pin controls the function of the
RD (DS), ALE (AS), and WR
(R/ W) pins. If BTS = 1, then these pins assume the function listed in
parentheses ().
HBE: In Hardware Mode (BIS[1:0] = 11), this pin enables transmit and
receive B8ZS/HDB3 when in T1/E1 operating modes.
RD(DS)/
RMODE2
I
Read Input-Data Strobe/Receive Mode Select Bit 2
RD (DS): These pins are active-low signals. DS is active high when BIS[1:0]
= 01. See the bus timing diagrams.
RMODE2: In Hardware Mode (BIS[1:0] = 11), this pin selects the receive
side operating mode.
CS/RLB I
Chip Select/Remote Loopback Enable
CS: This active-low signal must be low to read or write to the device. This
signal is used for both the parallel port and the serial port modes.
RLB: In Hardware Mode (BIS[1:0] = 11), when high, remote loopback is
enabled. This function is only valid when the transmit side and receive side
are in the same operating mode.
ALE (AS)/
A7/MPS1
I
Address Latch Enable (Address Strobe)/Address Bus Bit 7/MCLK
Prescale Select 1
ALE (AS): In multiplexed bus operation (BIS[1:0] = 00), it serves to
demultiplex the bus on a positive-going edge.
A7: In nonmultiplexed bus operation (BIS[1:0] = 01), this pin serves as A[7].
MPS1: In Hardware Mode (BIS[1:0] = 11), MCLK prescale select, used to set
the prescale value for the PLL.
WR (R/W)/
TMODE3
I
Write Input (Read/Write)/Transmit Mode Select 3
WR: In Processor Mode, this pin is the active-low write signal.
TMODE3: In Hardware Mode, this pin selects the transmit-side operating
mode.