Specifications

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ter, is also used in Multiply and Divide instructions.
The ALU generates several status signals that are
stored in the Program Status Word register (PSW).
A
A
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The Accumulator (ACC) is the primary register
used in arithmetic, logical and data transfer opera-
tions in the configurable system-on-chip. Since the
Accumulator is directly accessible by the microcon-
troller, most of the high-speed instructions use the
ACC as one argument.
B
B
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This 8-bit register is used as the second argument
in the MUL and DIV instructions. For all other in-
structions, it is simply a general-purpose register.
P
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This is an 8-bit SFR that stores the status bits of
the ALU. It holds the Carry flag, the Auxiliary
Carry flag, General purpose flags, the Register
Bank Select, the Overflow flag, and the Parity flag.
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D
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MOVX instructions use the Data Pointers to trans-
fer data to and from Data locations. These point-
ers hold the address of the memory location to
which data is transferred. Because data can be
moved to and from external memory, the configur-
able system-on-chip provides two separate Data
Pointers. The user can switch between either of
the two Data Pointers with minimum software
overhead, greatly increasing system throughput.
S
S
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The 8032 has a 256-byte scratchpad RAM within
the microcontroller. Scratchpad RAM is useful for
temporary storage during program execution. Cer-
tain sections of this RAM are bit addressable, and
directly addressed by the 8032’s powerful Boolean
instructions.
S
S
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k
k
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The 8032 has an 8-bit Stack Pointer that points to
the top of the Stack. The stack resides in the
scratchpad RAM in the processor. Consequently,
the size of the stack is limited by the size of this
RAM.
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T
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s
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/
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C
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The configurable system-on-chip has three 16-bit
Timer/Counters. Each timer inhabits two SFR lo-
cations that software can read or write. Other SFR
locations, associated with the timers, control their
mode and operation.
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The 8032 microcontroller provides one serial I/O
port that operates in both synchronous and asyn-
chronous modes. The serial port inhabits several
SFR locations.
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O
O
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The 8032, a classic Harvard architecture device,
separates the memory into two sections, the pro-
gram memory and the data memory. The program
memory stores the instruction op-codes, while the
data memory stores data values or accesses
memory-mapped devices.
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The 8032 supports up to 64K bytes of program
memory. This memory space is either stored ex-
ternally—typically in FLASH memory—or internally
using the ZE5’s internal system RAM. All instruc-
tions are fetched for execution from this memory
area. The MOVC instruction also accesses this
memory region.
D
D
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M
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The 8032 supports up to 64K bytes of data mem-
ory. This memory region is accessed by the
MOVX instructions. In addition, the 8032 micro-
controller has 256 bytes of scratchpad RAM, plus
can access an additional 8K bytes to 64K bytes of
internal system RAM—the memory size depends
on the specific device. Scratchpad RAM locations
are accessed either by direct addressing or by in-
direct addressing. The microcontroller’s Special
Function Registers (SFRs) can only be accessed
by direct addressing.
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The 8032 has separate program and data memory
areas. The on-chip 256-byte scratchpad RAM is in
addition to the on-chip system RAM and any ex-
ternal memory. There are also several SFRs ac-
cessed by software. The SFRs are only accessi-
ble through direct addressing, while the on-chip
scratchpad RAM is accessible through either direct
or indirect addressing.
Since the scratchpad RAM, shown in Figure 46, is
only 256 bytes deep, it can be used only when
data contents are small. Larger amounts of data
should be stored either in the internal system RAM
or in external data memory. However, on-chip sys-
tem RAM has faster access times than external
RAM. There are several other special-purpose
areas within the scratchpad RAM. These are de-
scribed as follows.