1998 Microchip Technology Inc.
Preliminary
DS40143C-page 5
PIC16C55X
1.0 GENERAL DESCRIPTION
The PIC16C55X are 18 and 20-Pin EPROM-based
members of the versatile PIC16CXX family of lo w-cost,
high-performance, CMOS, fully-static, 8-bit
microcontrollers.
All PICmicro
®
microcontrollers employ an advanced
RISC architecture. The PIC16C55X have enhanced
core features, eight-le vel deep stack, and multiple inter-
nal and external interrupt sources. The separate
instruction and data buses of the Harvard architecture
allow a 14-bit wide instruction word with the separate
8-bit wide data. The two-stage instruction pipeline
allows all instructions to execute in a single-cycle,
except for program branches (which require two
cycles). A total of 35 instructions (reduced instruction
set) are av ailable. Additionally, a large register set gives
some of the architectural innov ations used to achie v e a
very high performance.
PIC16C55X microcontrollers typically achieve a 2:1
code compression and a 4:1 speed improvement over
other 8-bit microcontrollers in their class.
The PIC16C554 has 80 bytes of RAM. The PIC16C558
has 128 bytes of RAM. Each de vice has 13 I/O pins and
an 8-bit timer/counter with an 8-bit programmab le pres-
caler.
PIC16C55X devices have special features to reduce
external components, thus reducing cost, enhancing
system reliability and reducing power consumption.
There are f our oscillator options, of which the single pin
RC oscillator provides a low-cost solution, the LP
oscillator minimizes power consumption, XT is a
standard crystal, and the HS is f or High Speed crystals.
The SLEEP (power-down) mode offers power saving.
The user can wake up the chip from SLEEP through
several external and internal interrupts and reset.
A highly reliable Watchdog Timer with its own on-chip
RC oscillator provides protection against software
lock-up.
A UV-erasable CERDIP-packaged version is ideal for
code development while the cost-effective One-Time
Programmable (OTP) version is suitable for production
in any volume.
Table 1-1 shows the features of the PIC16C55X
mid-range microcontroller families.
A simplified block diagram of the PIC16C55X is sho wn
in Figure 3-1.
The PIC16C55X series fit perfectly in applications
ranging from motor control to low-power remote sen-
sors. The EPROM technology makes customization of
application programs (detection levels, pulse genera-
tion, timers, etc.) extremely fast and convenient. The
small footprint packages make this microcontroller
series perfect f or all applications with space limitations .
Low-cost, low-power, high-performance, ease of use
and I/O flexibility make the PIC16C55X very versatile.
1.1 Family and Upward Compatibility
Those users familiar with the PIC16C5X family of
microcontrollers will realize that this is an enhanced
version of the PIC16C5X architecture. Please refer to
Appendix A for a detailed list of enhancements. Code
written for PIC16C5X can be easily ported to
PIC16C55X family of devices (Appendix B).
The PIC16C55X f amily fills the niche for users w anting
to migrate up from the PIC16C5X family and not need-
ing various peripheral f eatures of other members of the
PIC16XX mid-range microcontroller family.
1.2 Development Support
The PIC16C55X family is suppor ted by a full-featured
macro assembler, a software simulator, an in-circuit
emulator, a low-cost development programmer and a
full-featured programmer. A “C” compiler and fuzzy
logic support tools are also available.