PIC18LF2539T-I/SO Microchip Technology, PIC18LF2539T-I/SO Datasheet - Page 37

• Manufacturer Part Number: PIC18LF2539T-I/SO
• Description: IC MCU FLASH 12KX16 EE AD 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18LF2539T-I/SO

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 21
• Program Memory Size: 24KB (12K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1408 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Processor Series: PIC18LF
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1408 B
• Interface Type: I2C, SPI, AUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 16 bit
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: DV164005, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REGISTER 4-1:
FIGURE 4-2:
4.2.3
Since the Top-of-Stack (TOS) is readable and writable,
the ability to push values onto the stack and pull values
off the stack, without disturbing normal program execu-
tion, is a desirable option. To push the current PC value
onto the stack, a PUSH instruction can be executed.
This will increment the stack pointer and load the cur-
rent PC value onto the stack. TOSU, TOSH and TOSL
can then be modified to place a return address on the
stack.
The ability to pull the TOS value off of the stack and
replace it with the value that was previously pushed
onto the stack, without disturbing normal execution, is
achieved by using the POP instruction. The POP instruc-
tion discards the current TOS by decrementing the
stack pointer. The previous value pushed onto the
stack then becomes the TOS value.
 2002 Microchip Technology Inc.
bit 7
bit 6
bit 5
bit 4-0
PUSH AND POP INSTRUCTIONS
(1)
(1)
TOSU
STKPTR REGISTER
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
0x00
bit 7
STKFUL: Stack Full Flag bit
1 = Stack became full or overflowed
0 = Stack has not become full or overflowed
STKUNF: Stack Underflow Flag bit
1 = Stack underflow occurred
0 = Stack underflow did not occur
Unimplemented: Read as '0'
SP4:SP0: Stack Pointer Location bits
Legend:
R = Readable bit
- n = Value at POR
STKFUL
R/C-0
Note 1: Bit 7 and bit 6 can only be cleared in user software or by a POR.
STKUNF
TOSH
0x1A
R/C-0
Top-of-Stack
TOSL
0x34
U-0
Preliminary
—
W = Writable bit
‘1’ = Bit is set
Return Address Stack
R/W-0
SP4
0x001A34
0x000D58
4.2.4
These RESETS are enabled by programming the
STVREN configuration bit. When the STVREN bit is
disabled, a full or underflow condition will set the appro-
priate STKFUL or STKUNF bit, but not cause a device
RESET. When the STVREN bit is enabled, a full or
underflow condition will set the appropriate STKFUL or
STKUNF bit and then cause a device RESET. The
STKFUL or STKUNF bits are only cleared by the user
software or a POR Reset.
R/W-0
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
SP3
STACK FULL/UNDERFLOW RESETS
11111
11110
11101
00011
00010
00001
00000
STKPTR<4:0>
R/W-0
PIC18FXX39
SP2
00010
x = Bit is unknown
R/W-0
SP1
DS30485A-page 35
R/W-0
SP0
bit 0