MT9079 Mitel Semiconductor, MT9079 Datasheet - Page 39

• Manufacturer Part Number: MT9079
• Description: CMOS ST-BUS FAMILY Advanced Controller for E1
• Manufacturer: Mitel Semiconductor

The data link transmit and receive signals are
connected directly to port one. The DCLK signal is
connected to INT1 so the 80C52 will be interrupted
when new data link data needs to be transported.
Figure 9 illustrates a circuit that will interface the
MT9079 to the MC68302 microprocessor operating
at 20 MHz. CS0 was chosen so that no external
address decoding would be required. The MT9079
does not have a DTACK output therefore, the
MC68302 DTACK should be tied high. The data link
interface is handled by Non-multiplexed Serial
Interface port Two (NMSI2).
Figure 10 shows how to connect a 16 MHz 80C188
microprocessor to the MT9079. The 80C188 WR and
25pF
25pF
10k
+5V
+5V
+5V
700k
Figure 9 - MT9079 to MC68302 (20 MHz) Microprocessor Interface Circuit
Figure 10 - MT9079 to 80C188 (16 MHz) Microprocessor Interface Circuit
4.7k
EXTAL
XTAL
BERR
BGACK
AVEC
BR
FRZ
DISCPU
BUSW
UCS, or PCS
MC68302
80C188
LCS, MCS,
AD
CLKOUT
DTACK
RCLK2
TCLK2
0
D
BCLR
A
RxD2
TxD2
IRQ7
DT/R
-AD
ALE
CS0
LDS
R/W
0
0
NMI
WR
RD
-D
-A
7
4
7
10k
+5V
8
+5V
74F04
10k
74F04
74HCT04
74F86
10k
74F04
5
+5V
74F374
OE
Dn
10k
CP
RD signals are re-timed using the CLKOUT signal to
generate a DS signal for the MT9079. The inverted
form of DT/R is used to make a R/W signal, and the
ALE is used to latch the lower order address lines for
the duration of the access cycle.
MT9079 TAIS and Reset Circuit
Figure 11 illustrates a reset and transmit AIS circuit
that can be implemented with
microprocessor. This circuit has three purposes: 1)
to provide a power-on reset for the all the MT9079
devices; 2) to have all the MT9079 devices transmit
AIS during system initialization; and 3) to have all the
MT9079 devices transmit AIS when the MC68302
watch-dog time expires.
Qn
74F04
5
8
D
74F74
CLR
+5V
10k
Q
Q
10k
5
8
CS
IRQ
DS
R/W
AC
D
S/P
RxDL
TxDL
AC
DS
D
S/P
CS
DLCLK
R/W
IRQ
0
0
-D
-D
0
0
MT9079
MT9079
-AC
-AC
7
7
4
4
the
MT9079
MC68302
4-275