PIC12F683-E/P Microchip Technology Inc., PIC12F683-E/P Datasheet - Page 90

• Manufacturer Part Number: PIC12F683-E/P
• Description: 8 PIN, 3.5 KB FLASH, 128 RAM, 6 I/O, PDIP
• Manufacturer: Microchip Technology Inc.

Specifications of PIC12F683-E/P

• A/d Inputs: 4 Channel, 10-Bit
• Comparators: 1
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Frequency: 20 MHz
• Input Output: 6
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 8-pin PDIP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Serial Interface: None
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC12F683
12.5
During an interrupt, only the return PC value is saved
on the stack. Typically, users may wish to save key
registers during an interrupt (e.g., W and Status
registers). This must be implemented in software.
Since the lower 16 bytes of all banks are common in the
PIC12F683 (see Figure 2-2), temporary holding regis-
ters, W_TEMP and STATUS_TEMP, should be placed
in here. These 16 locations do not require banking and
therefore, makes it easier to context save and restore.
The same code shown in Example 12-1 can be used
to:
• Store the W register.
• Store the Status register.
• Execute the ISR code.
• Restore the Status (and Bank Select Bit register).
• Restore the W register.
EXAMPLE 12-1:
DS41211B-page 88
MOVWF
SWAPF
CLRF
MOVWF
:
:(ISR)
:
SWAPF
MOVWF
SWAPF
SWAPF
Context Saving During Interrupts
W_TEMP
STATUS,W
STATUS
STATUS_TEMP
STATUS_TEMP,W
STATUS
W_TEMP,F
W_TEMP,W
SAVING STATUS AND W REGISTERS IN RAM
;Copy W to TEMP register
;Swap status to be saved into W
;bank 0, regardless of current bank, Clears IRP,RP1,RP0
;Save status to bank zero STATUS_TEMP register
;Insert user code here
;Swap STATUS_TEMP register into W
;(sets bank to original state)
;Move W into Status register
;Swap W_TEMP
;Swap W_TEMP into W
Preliminary
Note:
The PIC12F683 normally does not require
saving the PCLATH. However, if com-
puted GOTOs are used in the ISR and the
main code, the PCLATH must be saved
and restored in the ISR.
 2004 Microchip Technology Inc.