HPC16064 Datasheet, PDF (31/36 Pages) National Semiconductor (TI) – High-Performance microController

Code Efficiency
One of the most important criteria of a single chip microcon-
troller is code efficiency The more efficient the code the
more features that can be put on a chip The memory size
on a chip is fixed so if code is not efficient features may
have to be sacrificed or the programmer may have to buy a
larger more expensive version of the chip
The HPC46064 has been designed to be extremely code-
efficient The HPC46064 looks very good in all the standard
coding benchmarks however it is not realistic to rely only
on benchmarks Many large jobs have been programmed
onto the HPC46064 and the code savings over other popu-
lar microcontrollers has been considerable
Reasons for this saving of code include the following
SINGLE BYTE INSTRUCTIONS
The majority of instructions on the HPC46064 are single-
byte There are two especially code-saving instructions JP
is a 1-byte jump True it can only jump within a range of plus
or minus 32 but many loops and decisions are often within
a small range of program memory Most other micros need
2-byte instructions for any short jumps
JSRP is a 1-byte call subroutine The user makes a table of
the 16 most frequently called subroutines and these calls
will only take one byte Most other micros require two and
even three bytes to call a subroutine The user does not
have to decide which subroutine addresses to put into this
table the assembler can give this information
EFFICIENT SUBROUTINE CALLS
The 2-byte JSR instructions can call any subroutine within
plus or minus 1k of program memory
MULTIFUNCTION INSTRUCTIONS FOR DATA
MOVEMENT AND PROGRAM LOOPING
The HPC46064 has single-byte instructions that perform
multiple tasks For example the XS instruction will do the
following
1 Exchange A and memory pointed to by the B register
2 Increment or decrement the B register
3 Compare the B register to the K register
4 Generate a conditional skip if B has passed K
The value of this multipurpose instruction becomes evident
when looping through sequential areas of memory and exit-
ing when the loop is finished
BIT MANIPULATION INSTRUCTIONS
Any bit of memory I O or registers can be set reset or
tested by the single byte bit instructions The bits can be
addressed directly or indirectly Since all registers and I O
are mapped into the memory it is very easy to manipulate
specific bits to do efficient control
DECIMAL ADD AND SUBTRACT
This instruction is needed to interface with the decimal user
world
It can handle both 16-bit words and 8-bit bytes
The 16-bit capability saves code since many variables can
be stored as one piece of data and the programmer does
not have to break his data into two bytes Many applications
store most data in 4-digit variables The HPC46064 supplies
8-bit byte capability for 2-digit variables and literal variables
MULTIPLY AND DIVIDE INSTRUCTIONS
The HPC46064 has 16-bit multiply 16-bit by 16-bit divide
and 32-bit by 16-bit divide instructions This saves both
code and time Multiply and divide can use immediate data
or data from memory The ability to multiply and divide by
immediate data saves code since this function is often
needed for scaling base conversion computing indexes of
arrays etc
Development Support
HPC Microcontroller Development
System
The HPC microcontroller development system is an in-sys-
tem emulator (lSE) designed to support the entire family of
HPC Microcontrollers The complete package of hardware
and software tools combined with a host system provides a
powerful system for design development and debug of HPC
based designs Software tools are available for IBM
PC-AT (MS-DOS PC-DOS) and for Unix based multi-user
Sun Sparcstation (SunOS^TM)
The stand alone units comes complete with a power supply
and extemal emulation POD This unit can be connected to
various host systems through an RS-232 link The software
package includes an ANSl compatible C-Compiler Linker
Assembler and librarian package Source symbolic debug
capability is provided through a user friendly MS-windows
3 0 interface for IBM PC-AT environment and through a line
debugger under Sunview for Sun Sparcstations
The lSE provides fully transparent in-system emulation at
speeds up to 20 MHz 1 waitstate A 2k word (48-bit wide)
trace buffer gives trace trigger and non-intrusive monitoring
of the system External triggering is also available through
an external logic interface socket on the POD Direct
EPROM programming can be done through the use of ex-
ternally mounted EPROM socket Form-Fit-Function emula-
tor programming is supported by a programming board in-
cluded with the system Comprehensive on-line help and
diagnostics features reduce user’s design and debug time
8 hardware breakpoints (Address range) 64 Kbytes of user
memory and break on external events are some of the oth-
er features offered
Hewlett Packard model HP64775 Emulator Analyzer pro-
viding in-system emulation for up to 30 MHz 1 waitstate is
also available Contact your local sales office for technical
details and support
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