70592C Datasheet, PDF (27/314 Pages) Microchip Technology – High-Performance, 16-bit Microcontrollers

PIC24HJXXXGPX06A/X08A/X10A
3.0 CPU
Note 1: This data sheet summarizes the features
of the PIC24HJXXXGPX06A/X08A/X10A
family of devices. However, it is not
intended to be a comprehensive
reference source. To complement the
information in this data sheet, refer to
Section 2. “CPU” (DS70245) of the
“dsPIC33F/PIC24H Family Reference
Manual”, which is available from the
Microchip website (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
The PIC24HJXXXGPX06A/X08A/X10A CPU module
has a 16-bit (data) modified Harvard architecture with an
enhanced instruction set and addressing modes. The
CPU has a 24-bit instruction word with a variable length
opcode field. The Program Counter (PC) is 23 bits wide
and addresses up to 4M x 24 bits of user program
memory space. The actual amount of program memory
implemented varies by device. A single-cycle instruction
prefetch mechanism is used to help maintain throughput
and provides predictable execution. All instructions
execute in a single cycle, with the exception of
instructions that change the program flow, the double
word move (MOV.D) instruction and the table instructions.
Overhead-free, single-cycle program loop constructs are
supported using the REPEAT instruction, which is
interruptible at any point.
The PIC24HJXXXGPX06A/X08A/X10A devices have
sixteen, 16-bit working registers in the programmer’s
model. Each of the working registers can serve as a data,
address or address offset register. The 16th working
register (W15) operates as a software Stack Pointer (SP)
for interrupts and calls.
The PIC24HJXXXGPX06A/X08A/X10A instruction set
includes many addressing modes and is designed for
optimum C compiler efficiency. For most instructions,
the PIC24HJXXXGPX06A/X08A/X10A is capable of
executing a data (or program data) memory read, a
working register (data) read, a data memory write and
a program (instruction) memory read per instruction
cycle. As a result, three parameter instructions can be
supported, allowing A + B = C operations to be
executed in a single cycle.
A block diagram of the CPU is shown in Figure 3-1,
and the programmer’s model for the
PIC24HJXXXGPX06A/X08A/X10A is shown in
Figure 3-2.
3.1 Data Addressing Overview
The data space can be linearly addressed as 32K words
or 64 Kbytes using an Address Generation Unit (AGU).
The upper 32 Kbytes of the data space memory map can
optionally be mapped into program space at any 16K
program word boundary defined by the 8-bit Program
Space Visibility Page (PSVPAG) register. The program to
data space mapping feature lets any instruction access
program space as if it were data space.
The data space also includes 2 Kbytes of DMA RAM,
which is primarily used for DMA data transfers, but may
be used as general purpose RAM.
3.2 Special MCU Features
The PIC24HJXXXGPX06A/X08A/X10A features a
17-bit by 17-bit, single-cycle multiplier. The multiplier
can perform signed, unsigned and mixed-sign
multiplication. Using a 17-bit by 17-bit multiplier for
16-bit by 16-bit multiplication makes mixed-sign
multiplication possible.
The PIC24HJXXXGPX06A/X08A/X10A supports 16/16
and 32/16 integer divide operations. All divide
instructions are iterative operations. They must be
executed within a REPEAT loop, resulting in a total
execution time of 19 instruction cycles. The divide
operation can be interrupted during any of those
19 cycles without loss of data.
A multi-bit data shifter is used to perform up to a 16-bit,
left or right shift in a single cycle.
© 2011 Microchip Technology Inc.
DS70592C-page 27