PIC16F716-I Datasheet, PDF (128/136 Pages) Microchip Technology – 8-bit Flash-based Microcontroller with A/D Converter and Enhanced Capture/Compare/PWM

PIC16F716
APPENDIX C: MIGRATION FROM
BASE-LINE TO
MID-RANGE DEVICES
This section discusses how to migrate from a baseline
device (i.e., PIC16C5X) to a mid-range device (i.e.,
PIC16F716).
The following are the list of modifications over the
PIC16C5X microcontroller family:
1. Instruction word length is increased to 14-bits.
This allows larger page sizes both in program
memory (2K now as opposed to 512 before) and
register file (128 bytes now versus 32 bytes
before).
2. A PC high latch register (PCLATH) is added to
handle program memory paging. Bits PA2, PA1,
PA0 are removed from STATUS register.
3. Data memory paging is redefined slightly.
STATUS register is modified.
4. Four new instructions have been added:
RETURN, RETFIE, ADDLW, and SUBLW.
Two instructions TRIS and OPTION are being
phased out although they are kept for
compatibility with PIC16C5X.
5. OPTION_REG and TRIS registers are made
addressable.
6. Interrupt capability is added. Interrupt vector is
at 0004h.
7. Stack size is increased to 8 deep.
8. Reset vector is changed to 0000h.
9. Reset of all registers is revisited. Five different
Reset (and wake-up) types are recognized.
Registers are reset differently.
10. Wake-up from Sleep through interrupt is added.
11. Two separate timers, Oscillator Start-up Timer
(OST) and Power-up Timer (PWRT) are
included for more reliable power-up. These
timers are invoked selectively to avoid
unnecessary delays on power-up and wake-up.
12. PORTB has weak pull-ups and interrupt-on-
change feature.
13. T0CKI pin is also a port pin (RA4) now.
14. FSR is made a full eight-bit register.
15. “In-circuit serial programming” is made possible.
The user can program PIC16F716 devices
using only five pins: VDD, VSS, MCLR/VPP, RB6
(clock) and RB7 (data in/out).
16. PCON STATUS register is added with a Power-
on Reset Status bit (POR).
17. Brown-out protection circuitry has been added.
Controlled by Configuration Word bits BOREN
and BORV. Brown-out Reset ensures the device
is placed in a Reset condition if VDD dips below
a fixed setpoint.
To convert code written for PIC16C5X to PIC16F716,
the user should take the following steps:
1. Remove any program memory page select
operations (PA2, PA1, PA0 bits) for CALL, GOTO.
2. Revisit any computed jump operations (write to
PC or add to PC, etc.) to make sure page bits
are set properly under the new scheme.
3. Eliminate any data memory page switching.
Redefine data variables to reallocate them.
4. Verify all writes to STATUS, OPTION, and FSR
registers since these have changed.
5. Change Reset vector to 0000h
.
Note 1: This device has been designed to
perform to the parameters of its data
sheet. It has been tested to an electrical
specification designed to determine its
conformance with these parameters. Due
to process differences in the manufacture
of this device, this device may have differ-
ent performance characteristics than its
earlier version. These differences may
cause this device to perform differently in
your application than the earlier version of
this device.
2: The user should verify that the device
oscillator starts and performs as
expected. Adjusting the loading capacitor
values and/or the Oscillator mode may be
required.
DS41206B-page 126
© 2007 Microchip Technology Inc.