PIC18F2455-I/SP Microchip Technology Inc., PIC18F2455-I/SP Datasheet - Page 211

• Manufacturer Part Number: PIC18F2455-I/SP
• Description: Microcontroller; 24 KB Flash; 2048 RAM; 256 EEPROM; 24 I/O; 28-Pin-SPDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F2455-I/SP

• A/d Inputs: 10-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 12 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 23
• Interface: I2C/SPI/USART/USB
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 24K Bytes
• Ram Size: 2K Bytes
• Speed: 48 MHz
• Timers: 1-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

18.5.2
The Configuration registers can be write-protected.
The WRTC bit controls protection of the Configuration
registers. In normal execution mode, the WRTC bit is
readable only. WRTC can only be written via ICSP
operation or an external programmer.
18.6
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.
18.7
PIC18F2450/4450 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.
18.8
When the DEBUG Configuration bit is programmed to
a ‘0’, the In-Circuit Debugger functionality is enabled.
This function allows simple debugging functions when
used with MPLAB
this feature enabled, some resources are not available
for general use. Table 18-4 shows which resources are
required by the background debugger.
TABLE 18-4:
© 2006 Microchip Technology Inc.
I/O pins:
Stack:
Program Memory:
Data Memory:
ID Locations
In-Circuit Debugger
In-Circuit Serial Programming
CONFIGURATION REGISTER
PROTECTION
®
DEBUGGER RESOURCES
IDE. When the microcontroller has
RB6, RB7
2 levels
512 bytes
10 bytes
Advance Information
To use the In-Circuit Debugger function of the
microcontroller, the design must implement In-Circuit
Serial Programming connections to MCLR/V
V
In-Circuit Debugger module available from Microchip
or one of the third party development tool companies.
18.9
Under specific circumstances, the No Connect (NC)
pins of PIC18F4450 devices in 44-pin TQFP packages
can provide additional functionality. These features are
controlled by device Configuration bits and are
available only in this package type and pin count.
18.9.1
The 44-pin TQFP devices can use NC pins to provide an
alternate port for In-Circuit Debugging (ICD) and In-
Circuit Serial Programming (ICSP). These pins are
collectively known as the dedicated ICSP/ICD port, since
they are not shared with any other function of the device.
When implemented, the dedicated port activates three
NC pins to provide an alternate device Reset, data and
clock ports. None of these ports overlap with standard
I/O pins, making the I/O pins available to the user’s
application.
The dedicated ICSP/ICD port is enabled by setting the
ICPRT Configuration bit. The port functions the same
way as the legacy ICSP/ICD port on RB6/RB7.
Table 18-5 identifies the functionally equivalent pins for
ICSP and ICD purposes.
TABLE 18-5:
MCLR/V
RE3
RB6/KBI2/
PGC
RB7/KBI3/
PGD
Legend:
DD
Legacy
, V
Port
SS
Pin Name
PP
Special ICPORT Features
(Designated Packages Only)
PIC18F2450/4450
, RB7 and RB6. This will interface to the
/
I = Input, O = Output, P = Power
DEDICATED ICD/ICSP PORT
NC/ICRST/
ICV
NC/ICCK/
ICPGC
NC/ICDT/
ICPGD
Dedicated
PP
EQUIVALENT PINS FOR
LEGACY AND DEDICATED
ICD/ICSP™ PORTS
Port
Type
Pin
I/O
P
I
Device Reset and
Programming
Enable
Serial Clock
Serial Data
DS39760A-page 209
Pin Function
PP
/RE3,