
PIC18F1230/1330
DS39758D-page 210
2009 Microchip Technology Inc.
20.5.2
DATA EEPROM
CODE PROTECTION
The entire data EEPROM is protected from external
reads and writes by two bits: CPD and WRTD. CPD
inhibits external reads and writes of data EEPROM.
WRTD inhibits internal and external writes to data
EEPROM. The CPU can always read data EEPROM
under normal operation, regardless of the protection bit
settings.
20.5.3
CONFIGURATION REGISTER
PROTECTION
The Configuration registers can be write-protected.
The WRTC bit controls protection of the Configuration
registers. In normal execution mode, the WRTC bit is
read-only. WRTC can only be written via ICSP
operation or an external programmer.
20.6
ID Locations
Eight memory locations (200000h-200007h) are
designated as ID locations, where the user can store
checksum or other code identification numbers. These
locations are both readable and writable during normal
execution through the TBLRD and TBLWT instructions
or during program/verify. The ID locations can be read
when the device is code-protected.
20.7
In-Circuit Serial Programming
PIC18F1230/1330 microcontrollers can be serially
programmed while in the end application circuit. This is
simply done with two lines for clock and data and three
other lines for power, ground and the programming
voltage. This allows customers to manufacture boards
with unprogrammed devices and then program the
microcontroller just before shipping the product. This
also allows the most recent firmware or a custom
firmware to be programmed.
20.8
In-Circuit Debugger
When the BKBUG Configuration bit is programmed to
a ‘0’, the In-Circuit Debugger functionality is enabled.
This function allows simple debugging functions when
used with MPLAB IDE. When the microcontroller has
this feature enabled, some resources are not available
for general use.
Table 20-4 shows which resources are
required by the background debugger.
TABLE 20-4:
DEBUGGER RESOURCES
To use the In-Circuit Debugger function of the microcon-
troller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP/RA5/FLTA,
VDD, VSS, RB7/PWM5/PGD and RB6/PWM4/PGC. This
will interface to the In-Circuit Debugger module available
from Microchip or one of the third party development tool
companies.
20.9
Single-Supply ICSP Programming
The PIC18F1230/1330 device family does not support
Low-Voltage ICSP Programming or LVP. This device
family can only be programmed using high-voltage ICSP
programming.
For
more
details,
refer
to
the
“PIC18F1230/1330 Flash Microcontroller Programming
Specification”
(DS39752).
Memory that is not code-protected can be erased using
either a block erase, or erased row by row, then written
at any specified VDD. If code-protected memory is to be
erased, a block erase is required.
I/O pins:
RB6, RB7
Stack:
2 levels
Program Memory:
512 bytes
Data Memory:
10 bytes