PIC18F2550-I/SP Microchip Technology Inc., PIC18F2550-I/SP Datasheet - Page 59

• 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

5.0
There are three types of memory in PIC18 enhanced
microcontroller devices:
• Program Memory
• Data RAM
• Data EEPROM
As Harvard architecture devices, the data and program
memories use separate busses; this allows for con-
current access of the two memory spaces. The data
EEPROM, for practical purposes, can be regarded as
a peripheral device, since it is addressed and accessed
through a set of control registers.
Additional detailed information on the operation of the
Flash program memory is provided in Section 6.0
“Flash Program Memory”. Data EEPROM is
discussed separately in Section 7.0 “Data EEPROM
Memory”.
FIGURE 5-1:
© 2006 Microchip Technology Inc.
CALL, RCALL, RETURN,
RETFIE, RETLW, CALLW,
ADDULNK, SUBULNK
MEMORY ORGANIZATION
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector
Program Memory
Stack Level 31
PIC18FX455
Stack Level 1
Reset Vector
PC<20:0>
Read ‘0’
On-Chip
PROGRAM MEMORY MAP AND STACK FOR PIC18F2455/2550/4455/4550 DEVICES
21
0000h
0018h
5FFFh
6000h
1FFFFFh
200000h
PIC18F2455/2550/4455/4550
Preliminary
CALL, RCALL, RETURN,
RETFIE, RETLW, CALLW,
ADDULNK, SUBULNK
5.1
PIC18 microcontrollers implement a 21-bit program
counter which is capable of addressing a 2-Mbyte
program memory space. Accessing a location between
the upper boundary of the physically implemented
memory and the 2-Mbyte address will return all ‘0’s (a
NOP instruction).
The PIC18F2455 and PIC18F4455 each have
24 Kbytes of Flash memory and can store up to 12,288
single-word
PIC18F4550 each have 32 Kbytes of Flash memory
and can store up to 16,384 single-word instructions.
PIC18 devices have two interrupt vectors. The Reset
vector address is at 0000h and the interrupt vector
addresses are at 0008h and 0018h.
The program memory maps for PIC18FX455 and
PIC18FX550 devices are shown in Figure 5-1.
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector
Program Memory Organization
Program Memory
instructions.
Stack Level 31
PIC18FX550
Stack Level 1
Reset Vector
PC<20:0>
On-Chip
Read ‘0’
21
The
0000h
0018h
7FFFh
8000h
1FFFFFh
200000h
PIC18F2550
DS39632C-page 57
and