PIC18F2455-I/SP Microchip Technology Inc., PIC18F2455-I/SP Datasheet - Page 50

• 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

PIC18F2450/4450
4.6
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal oper-
ation. Status bits from the RCON register, RI, TO, PD,
TABLE 4-3:
DS39760A-page 48
Power-on Reset
RESET Instruction
Brown-out
MCLR during Power-Managed
Run modes
MCLR during Power-Managed
Idle modes and Sleep mode
WDT Time-out during Full Power or
Power-Managed Run modes
MCLR during Full Power Execution
Stack Full Reset (STVREN = 1)
Stack Underflow Reset
(STVREN = 1)
Stack Underflow Error (not an actual
Reset, STVREN = 0)
WDT Time-out during Power-Managed
Idle or Sleep modes
Interrupt Exit from
Power-Managed modes
Legend: u = unchanged
Note 1:
2:
Reset State of Registers
When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the
interrupt vector (008h or 0018h).
Reset state is ‘1’ for POR and unchanged for all other Resets when software BOR is enabled
(BOREN1:BOREN0 Configuration bits = 01 and SBOREN = 1); otherwise, the Reset state is ‘0’.
Condition
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION
FOR RCON REGISTER
Program
PC + 2
Counter
PC + 2
0000h
0000h
0000h
0000h
0000h
0000h
0000h
0000h
0000h
0000h
Advance Information
(1)
SBOREN
u
u
u
u
u
u
u
u
u
u
u
1
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
(2)
POR and BOR, are set or cleared differently in different
Reset situations as indicated in Table 4-3. These bits
are used in software to determine the nature of the
Reset.
Table 4-4 describes the Reset states for all of the
Special Function Registers. These are categorized by
Power-on and Brown-out Resets, Master Clear and
WDT Resets and WDT wake-ups.
RI
RCON Register
1
0
1
u
u
u
u
u
u
u
u
u
TO
1
u
1
1
1
0
u
u
u
u
0
u
PD
1
u
1
u
0
u
u
u
u
u
0
0
POR BOR STKFUL STKUNF
0
u
u
u
u
u
u
u
u
u
u
u
© 2006 Microchip Technology Inc.
0
u
0
u
u
u
u
u
u
u
u
u
STKPTR Register
0
u
u
u
u
u
u
1
u
u
u
u
0
u
u
u
u
u
u
u
1
1
u
u