PIC18F13K22-I/SO Microchip Technology, PIC18F13K22-I/SO Datasheet - Page 30

• Manufacturer Part Number: PIC18F13K22-I/SO
• Description: IC MCU 8BIT 8KB FLASH 20SOIC
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F13K22-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 8KB (4K x 16)
• Package / Case: 20-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 64MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 17
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: I2C, MSSP, SPI, USART
• Maximum Clock Frequency: 64 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 4
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 12 Channel
• Package: 20SOIC W
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 64 MHz
• A/d Bit Size: 10 bit
• A/d Channels Available: 12
• Height: 2.05 mm
• Length: 12.8 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.8 V, 2.7 V
• Width: 7.5 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC18F1XK22/LF1XK22
3.1.2.4
Device Resets on Stack Overflow and Stack Underflow
conditions are enabled by setting the STVREN bit in
Configuration Register 4L. When STVREN is set, a full
or underflow will set the appropriate STKOVF or
STKUNF bit and then cause a device Reset. When
STVREN is cleared, a full or underflow condition will set
the appropriate STKOVF or STKUNF bit but not cause
a device Reset. The STKOVF or STKUNF bits are
cleared by the user software or a Power-on Reset.
3.1.3
A fast register stack is provided for the STATUS,
WREG and BSR registers, to provide a “fast return”
option for interrupts. The stack for each register is only
one level deep and is neither readable nor writable. It is
loaded with the current value of the corresponding reg-
ister when the processor vectors for an interrupt. All
interrupt sources will push values into the stack regis-
ters. The values in the registers are then loaded back
into their associated registers if the RETFIE, FAST
instruction is used to return from the interrupt.
If both low and high priority interrupts are enabled, the
stack registers cannot be used reliably to return from
low priority interrupts. If a high priority interrupt occurs
while servicing a low priority interrupt, the stack register
values stored by the low priority interrupt will be
overwritten. In these cases, users must save the key
registers by software during a low priority interrupt.
If interrupt priority is not used, all interrupts may use the
fast register stack for returns from interrupt. If no
interrupts are used, the fast register stack can be used
to restore the STATUS, WREG and BSR registers at
the end of a subroutine call. To use the fast register
stack for a subroutine call, a CALL label, FAST
instruction must be executed to save the STATUS,
WREG and BSR registers to the fast register stack. A
RETURN, FAST instruction is then executed to restore
these registers from the fast register stack.
Example 3-1 shows a source code example that uses
the fast register stack during a subroutine call and
return.
EXAMPLE 3-1:
DS41365D-page 30
CALL SUB1, FAST
SUB1
RETURN, FAST




FAST REGISTER STACK
Stack Overflow and Underflow
Resets
FAST REGISTER STACK
CODE EXAMPLE
;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
Preliminary
3.1.4
There may be programming situations that require the
creation of data structures, or look-up tables, in
program memory. For PIC18 devices, look-up tables
can be implemented in two ways:
• Computed GOTO
• Table Reads
3.1.4.1
A computed GOTO is accomplished by adding an offset
to the program counter. An example is shown in
Example 3-2.
A look-up table can be formed with an ADDWF PCL
instruction and a group of RETLW nn instructions. The
W register is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCL instruction. The next
instruction executed will be one of the RETLW
instructions that returns the value ‘nn’ to the calling
function.
The offset value (in WREG) specifies the number of
bytes that the program counter should advance and
should be multiples of 2 (LSb = 0).
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
EXAMPLE 3-2:
3.1.4.2
A better method of storing data in program memory
allows two bytes of data to be stored in each instruction
location.
Look-up table data may be stored two bytes per pro-
gram word by using table reads and writes. The Table
Pointer (TBLPTR) register specifies the byte address
and the Table Latch (TABLAT) register contains the
data that is read from or written to program memory.
Data is transferred to or from program memory one
byte at a time.
Table read and table write operations are discussed
further in Section 4.1 “Table Reads and Table
Writes”.
ORG
TABLE
MOVF
CALL
nn00h
ADDWF
RETLW
RETLW
RETLW
.
.
.
LOOK-UP TABLES IN PROGRAM
MEMORY
Computed GOTO
Table Reads and Table Writes
OFFSET, W
TABLE
PCL
nnh
nnh
nnh
AN OFFSET VALUE
COMPUTED GOTO USING
 2010 Microchip Technology Inc.
nn