PIC18F2550-I/SP Microchip Technology Inc., PIC18F2550-I/SP Datasheet - Page 307

• Manufacturer Part Number: PIC18F2550-I/SP
• Description: Microcontroller; 32 KB Flash; 2048 RAM; 256 EEPROM; 24 I/O; 28-Pin-SPDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F2550-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: 32K 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

25.5.2
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 continue to read and write
data EEPROM regardless of the protection bit settings.
25.5.3
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.
25.6
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.
25.7
PIC18F2455/2550/4455/4550 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 manu-
facture 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.
25.8
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 25-4 shows which resources are
required by the background debugger.
TABLE 25-4:
© 2006 Microchip Technology Inc.
I/O pins:
Stack:
Program Memory:
Data Memory:
ID Locations
In-Circuit Debugger
In-Circuit Serial Programming
DATA EEPROM
CODE PROTECTION
CONFIGURATION REGISTER
PROTECTION
®
DEBUGGER RESOURCES
IDE. When the microcontroller has
RB6, RB7
2 levels
512 bytes
10 bytes
PIC18F2455/2550/4455/4550
Preliminary
To use the In-Circuit Debugger function of the micro-
controller, the design must implement In-Circuit Serial
Programming connections to MCLR/V
V
Debugger module available from Microchip or one of
the third party development tool companies.
25.9
Under specific circumstances, the No Connect (NC)
pins of PIC18F4455/4550 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.
25.9.1
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 25-5 identifies the functionally equivalent pins for
ICSP and ICD purposes.
TABLE 25-5:
MCLR/V
RE3
RB6/KBI2/
PGC
RB7/KBI3/
PGD
Legend:
SS
Legacy
, RB7 and RB6. This will interface to the In-Circuit
Port
Pin Name
PP
Special ICPORT Features
(Designated Packages Only)
/
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
DS39632C-page 305
Device Reset and
Programming
Enable
Serial Clock
Serial Data
Pin Function
PP
/RE3, V
DD
,