Table of Contents
Advertisement
Table 2-10
NS87336VLJ Pin Descriptions (continued)
Pin
No.
/RI1
70, 62
/RI2
/RTS1
74, 66
/RTS2
SIN1
75, 67
SIN2
SIRQ1
60,
SIRQ2
51,
SIRQ4
49
SLCT
82
/SLIN
81
SOUT1
73, 65
SOUT2
/STB
95
/STEP
40
(Normal Mode)
/STEP
81
(PPM Mode)
I/O
Description
I
UARTs Ring Indicator. When low, this indicates that a telephone
ring signal has been received by the modem. The /RI signal is a
modem status input whose condition is tested by the CPU by reading
bit 6 (RI) of the Modem Status Register (MSR) for the appropriate
serial channel. Bit 6 is the complement of the RI signal. Bit 2 (
TERI) of the MSR indicates whether the RI input has changed from
low to high since the previous reading of the MSR.
NOTE: When the TERI bit of the MSR is set and Modem Status
interrupts are enabled, an interrupt is generated.
O
UARTs Request to Send. When low, this output indicates to the
modem or data set that the UART is ready to exchange data. The
RTS signal can be set to an active low by programming bit 1 (RTS) of
the Modem Control Register to a high level.
operation sets this signal to its inactive (high) state. Loop mode
operation holds this signal to its inactive state.
I
UARTs Serial Input. This input receives composite serial data from
the communications link (peripheral device, modem, or data set).
I
System interrupt 1, 2, and 3. This input can be routed to one of the
following output pins: IRQ3-IRQ7, IRQ9-IRQ12.
SIRQ13 can be also routed to IRQ15.
determines to which output pin the input pin is routed to.
SIRQ1 is multiplexed with IRQ15, SRIQ12 is multiplexed with
DRATE1/MSEN1/CS0,
DRV2/PNF/DR23.
I
Parallel Port Select. This input is set high by the printer when it is
selected. This pin has a nominal 25 KΩ pull-down resistor attached
to it.
I/O
Parallel Port Select Input. When this signal is low, it selects the
printer. This pin is in a tristate condition 10 ns after a 0 is loaded into
the corresponding Control Register bit. The system should pull this
pin high using a 4.7 KΩ resistor.
O
UARTs Serial Output. This output sends composite serial data to
the communications link (peripheral device, modem, or data set).
The SOUT signal is set to a marking state (logic 1) after a Master
Reset operation.
I/O
Parallel Port Data Strobe. This output indicates to the printer that a
valid data is available at the printer port. This pin is in a tristate
condition 10 ns after a 0 is loaded into the corresponding Control
Register bit. The system should pull high using a 4.7 KΩ.
O
FDC Step. This output signal issues pulses to the disk drive at a
software programmable rate to move the head during a seek
operation.
O
FDC Step. This pin gives an additional step signal in PPM Mode
when PNF = 0.
Software configuration
and
SIRQ3
is
A Master Reset
SIRQ12 and
multiplexed
with
Advertisement
Table of Contents
