PIC18F2585-I/SO Microchip Technology, PIC18F2585-I/SO Datasheet - Page 5

• Manufacturer Part Number: PIC18F2585-I/SO
• Description: IC MCU FLASH 24KX16 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2585-I/SO

• Core Size: 8-Bit
• Program Memory Size: 48KB (24K x 16)
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.25K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Controller Family/series: PIC18
• No. Of I/o's: 25
• Eeprom Memory Size: 1024Byte
• Ram Memory Size: 3.25KB
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 3.25 KB
• Interface Type: I2C, SPI, EUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 28
• Number Of Timers: 1 x 8
• Operating Supply Voltage: 4.2 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: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DM163011, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MILI3-DB18F4680 - BOARD DAUGHTER ICEPIC3
• Lead Free Status / Rohs Status: Details

19. Module: Interrupts
EXAMPLE 2:
© 2007 Microchip Technology Inc.
ISR @ 0x0008
Foo:
If an interrupt occurs during a two-cycle instruction
that modifies the STATUS, BSR or WREG register,
the unmodified value of the register will be saved
to the corresponding Fast Return (Shadow)
register. Upon a fast return from the interrupt, the
unmodified value will be restored to the STATUS,
BSR or WREG register.
For example, if a high priority interrupt occurs dur-
ing the instruction “MOVFF TEMP, WREG”, the
MOVFF instruction will be completed and WREG
will be loaded with the value of TEMP before
branching to ISR. However, the previous value of
WREG will be saved to the Fast Return register
during ISR branching. Upon return from the inter-
rupt with a fast return, the previous value of WREG
in the Fast Return register will be written to WREG.
This results in WREG containing the value it had
before execution of MOVFF TEMP, WREG.
Affected instructions are:
MOVFF
where Fd is WREG, BSR or STATUS;
MOVSF
where Fd is WREG, BSR or STATUS; and
MOVSS
where the destination is WREG, BSR or STATUS.
2. C Language Programming: The exact work
CALL
POP
:
:
RETFIE
around depends on the compiler in use. Please
refer to your C compiler documentation for
more details.
If using the Microchip MPLAB
define both high and low priority interrupt han-
dler functions as “low priority” by using the
pragma interruptlow directive.
This directive instructs the compiler to not use
the RETFIE FAST instruction. If the proper high
priority interrupt bit is set in the IPRx register,
then the interrupt is treated as high priority in
spite of the pragma interruptlow directive.
The code segment, shown in Example 3 on the
next page, demonstrates the work around
using the C18 compiler.
Fs, Fd
Zs, Fd
[Zs], [Zd]
Foo, FAST
FAST
®
C18 C Compiler,
; store current value of WREG, BSR, STATUS for a second time
; clears return address of Foo call
; insert high priority ISR code here
PIC18F2585/2680/4585/4680
Work around
1. Assembly Language Programming:
a)
b)
If any two-cycle instruction is used to
modify the WREG, BSR or STATUS
register, do not use the RETFIE FAST
instruction to return from the interrupt.
Instead, save/restore WREG, BSR and
STATUS via software per Example 8-1
in the Device Data Sheet. Alternatively,
in the case of MOVFF, use the MOVF
instruction to write to WREG instead.
For example, use:
MOVF
MOVWF BSR
instead of MOVFF TEMP, BSR.
As another alternative, the following
work around shown in Example 2 can
be used. This example overwrites the
Fast Return register by making a
dummy call to Foo with the fast option
in the high priority service routine.
TEMP, W
DS80202G-page 5