IEEE 488.2 Controller Chip
NAT9914
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Available as RoHS-compliant
Pin compatible with TI TMS9914A
Software compatible with NEC µPD7210
or TI TMS9914A controller chips
Low power consumption
Meets all IEEE 488.2 requirements
– Bus line monitoring
– Preferred implementation of
requesting service
– Will not send messages when there
are no Listeners
Performs all IEEE 488.1 interface
functions
Programmable data transfer rate
(T1 delays of 350 ns, 500 ns, 1.1 µs,
and 2 µs)
Automatic EOS and/or NL message
detection
Direct memory access (DMA)
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Automatically processes IEEE 488
commands and reads undened
commands
TTL-compatible CMOS device
Programmable clock rate
20 MHz maximum
Reduces driver overhead
Does not lose a data byte
if ATN is asserted while
transmitting data
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Description
The NAT9914 IEEE 488.2 controller chip can perform all the
interface functions dened by the IEEE Standard 488.1-1987,
and also meets the additional requirements and
recommendations of the IEEE Standard 488.2-1987.
Connected between the processor and the IEEE 488 bus, the
NAT9914 provides high-level management of the IEEE 488
bus, signicantly increases the throughput of driver software,
and simplifies both the hardware and software design. The
NAT9914 performs complete IEEE 488 Talker, Listener,
and Controller functions. In addition to its numerous
improvements, the NAT9914 is also completely pin
compatible with the TI TMS 9914A and software compatible
with the NEC µPD7210 and TI TMS9914A controller chips.
General
The NAT9914 manages the IEEE 488 bus. You program the
IEEE 488 bus by writing control words into the appropriate
registers. CPU-readable status registers supply operational
feedback. The NAT9914 mode determines the function of
these registers. On power up or reset, the NAT9914 registers
resemble those of the TMS9914A set, with additional registers
that supply extra functionality and IEEE 488.2 compatibility. In
this mode, the NAT9914 is completely pin compatible with the
TI TMS9914A. If you enable the 7210 mode, the registers
resemble those of the NEC µPD7210 set, with additional
registers that supply extra functionality and IEEE 488.2
compatibility. This mode is not pin compatible with the
NEC µPD7210. Figure 4 shows the key components of the
NAT9914.
IEEE 488.2 Overview
The IEEE 488.2 standard removes the ambiguities of
IEEE 488.1 by standardizing the way instruments and
controllers operate. It defines data formats, status reporting,
error handling, and common configuration commands to
which all IEEE 488.2 instruments must respond in a precise
manner. It also denes a set of controller requirements. With
IEEE 488.2, you gain the benets of reduced development time
and cost because systems are more compatible and reliable.
The NAT9914 brings the full power of IEEE 488.2 to the
design engineer along with numerous other design and
performance benefits, while retaining the 40-pin and 44-pin
hardware congurations of the TI TMS 9914A.
RoHS Compliance
The NAT9914 is currently available from NI both in a standard
package and as a RoHS-compliant chip. The chips can be
ordered using the part numbers shown in the Ordering
Information box below. The RoHS-compliant parts are
identified through the added “F” at the end of the part number
and the chip itself is marked with an e3 inside an ellipse to
indicate a matte pure tin finish on the leads, in accordance
with the marking recommendations defined in JEDEC
JESD97.
The RoHS-compliant NAT9914 meets industry requirements
for baking and maximum solder reflow temperature. The
baking requirements are outlined in JEDEC J-STD-033, and
NI [ NATIONAL INSTRUMENTS CORPORATION ]
