Major Chips Description 2-79

2.7.4 Pin Description

Table 2-14 NS87336VJG Pin Descriptions

Pin No. I/O Description
A15-A0 67, 64,
62-60,
29, 19-
28
IAddress. These address lines from the microprocessor determine which
internal register is accessed. A0-A15 are don't cares during DMA
transfer.
/ACK 83 IParallel Port Acknowledge. This input is pulsed low by the printer to
indicate that it has received the data from the parallel port. This pin has
a nominal 25 K pull-up resistor attached to it.
ADRATE0,
ADRATE1 96,
46 OFDD Additional Data Rate 0,1. These outputs are similar to DRATE0, 1.
They are provided in addition to DRATE0, 1. They reflect the currently
selected FDC data rate, (bits 0 and 1 in the Configuration Control
Register (CCR) or the Data Rate Select Register (DSR), whichever was
written to last). ADRATE0 is configured when bit 0 of ASC is 1.
ADRATE1 is configured when bit 4 of ASC is 1. (See IRQ5 and
DENSEL for further information).
/AFD 76 I/O Parallel Port Automatic Feed XT. When this signal is low, the printer
automatically line feed after printing each line. 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 K
resistor.
AEN 18 IAddress Enable. When this input is high, it disables function selection
via A15-A0. Access during DMA transfer is not affected by this pin.
/ASTRB 79 OEPP Address Strobe. This signal is used in EPP mode as address
strobe. It is an active low signal.
BADDR0,
BADDR1 72,
71 IBase Address. These bits determine one of the four base addresses
from which the Index and Data Registers are offset. An internal pull-
down resistor of 30 K is on this pin. Use a 10 K resistor to pull this
pin to VCC.
BOUT1,
BOUT2 71,
63 OUARTs Baud Output. This multi-function pin supports the associated
serial channel Baud Rate generator output signal if the test mode is
selected in the Power and Test Configuration Register and the DLAB bit
(LCR7) is set. After the Master Reset, this pin offers the SOUT function.
BUSY 82 IParallel Port Busy. This pin is set high by the printer when it cannot
accept another character. It has a nominal 25 K pull-down resistor
attached to it.
CFG0
CFG1 63,
69 IConfiguration on Power-up. These CMOS inputs select 1 of 4 default
configurations in which the PC87336 powers up. An internal pull-down
resistor of 30 K is on each pin. Use a 10 K resistor to pull these pins
to VCC.