IEEE 488.2 Controller Chip
Drop-In Replacement for TI TMS9914A
NAT9914APD
NAT9914APL
Features
• 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)
• Automatically processes IEEE 488
commands and reads undefined commands
• TTL-compatible CMOS device
• Programmable clock rate up to 20 MHz
• Reduces driver overhead
– Does not lose a data byte if ATN is
asserted while transmitting data
NAT9914
Description
The NAT9914 IEEE 488.2 controller chip
can perform all the interface functions defined
by that 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, significantly 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.
for the test system developer are 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 configurations
of the TI TMS 9914A.
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 the TMS9914A register
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 the NEC µPD7210 register set
with additional registers that supply extra
functionality and IEEE 488.2 compatibility.
This mode is not pin compatible with the
NECµPD7210. Figure 2 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 defines a set of controller
requirements. The benefits of IEEE 488.2
Note:
For more details about the NAT9914 see the NAT9914 Reference Manual, Part Number 320775-01.
340497B-01
071596
NI [ NATIONAL INSTRUMENTS CORPORATION ]
