PIC16F84A-20/SO Microchip Technology, PIC16F84A-20/SO Datasheet - Page 32
PIC16F84A-20/SO
Manufacturer Part Number
PIC16F84A-20/SO
Description
IC MCU FLASH 1KX14 EE 18SOIC
Manufacturer
Microchip Technology
Series
PIC® 16Fr
Datasheets
1.PIC16F688T-ISL.pdf
(688 pages)
2.PIC16F84A-04P.pdf
(88 pages)
3.PIC16F84A-04P.pdf
(6 pages)
Specifications of PIC16F84A-20/SO
Core Size
8-Bit
Program Memory Size
1.75KB (1K x 14)
Core Processor
PIC
Speed
20MHz
Peripherals
POR, WDT
Number Of I /o
13
Program Memory Type
FLASH
Eeprom Size
64 x 8
Ram Size
68 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 5.5 V
Oscillator Type
External
Operating Temperature
0°C ~ 70°C
Package / Case
18-SOIC (7.5mm Width)
Controller Family/series
PIC16F
No. Of I/o's
13
Eeprom Memory Size
64Byte
Ram Memory Size
68Byte
Cpu Speed
20MHz
No. Of Timers
1
Processor Series
PIC16F
Core
PIC
Data Bus Width
8 bit
Data Ram Size
68 B
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
13
Number Of Timers
8
Operating Supply Voltage
2 V to 5.5 V
Maximum Operating Temperature
+ 70 C
Mounting Style
SMD/SMT
3rd Party Development Tools
52715-96, 52716-328, 52717-734
Development Tools By Supplier
ICE2000
Minimum Operating Temperature
0 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
XLT18SO-1 - SOCKET TRANSITION 18SOIC 300MILI3-DB16F84A - BOARD DAUGHTER ICEPIC3309-1075 - ADAPTER 18-SOIC TO 18-SOIC309-1011 - ADAPTER 18-SOIC TO 18-DIP309-1010 - ADAPTER 18-SOIC TO 18-DIPAC164010 - MODULE SKT PROMATEII DIP/SOIC
Data Converters
-
Connectivity
-
Lead Free Status / Rohs Status
Details
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
PIC16F84A
6.9
During an interrupt, only the return PC value is saved
on the stack. Typically, users wish to save key register
values during an interrupt (e.g., W register and
STATUS register). This is implemented in software.
The code in Example 6-1 stores and restores the
STATUS and W register’s values. The user defined
registers, W_TEMP and STATUS_TEMP are the tem-
porary storage locations for the W and STATUS
registers values.
EXAMPLE 6-1:
6.10
The Watchdog Timer is a free running On-Chip RC
Oscillator which does not require any external
components. This RC oscillator is separate from the
RC oscillator of the OSC1/CLKIN pin. That means that
the WDT will run even if the clock on the OSC1/CLKIN
and OSC2/CLKOUT pins of the device has been
stopped, for example, by execution of a SLEEP
instruction. During normal operation, a WDT time-out
generates a device RESET. If the device is in SLEEP
mode, a WDT wake-up causes the device to wake-up
and continue with normal operation. The WDT can be
permanently disabled by programming configuration bit
WDTE as a '0' (Section 6.1).
DS35007B-page 30
PUSH
ISR
POP
Context Saving During Interrupts
Watchdog Timer (WDT)
MOVWF
SWAPF
MOVWF
:
:
:
:
SWAPF
MOVWF
SWAPF
SWAPF
W_TEMP
STATUS,
STATUS_TEMP
STATUS_TEMP,W
STATUS
W_TEMP,
W_TEMP,
SAVING STATUS AND W REGISTERS IN RAM
W
F
W
; Copy W to TEMP register,
; Swap status to be saved into W
; Save status to STATUS_TEMP register
:
; Interrupt Service Routine
; should configure Bank as required
;
; Swap nibbles in STATUS_TEMP register
; and place result into W
; Move W into STATUS register
; (sets bank to original state)
; Swap nibbles in W_TEMP and place result in W_TEMP
; Swap nibbles in W_TEMP and place result into W
Example 6-1 does the following:
a)
b)
c)
d)
e)
6.10.1
The WDT has a nominal time-out period of 18 ms, (with
no prescaler). The time-out periods vary with
temperature, V
part (see DC specs). If longer time-out periods are
desired, a prescaler with a division ratio of up to 1:128
can be assigned to the WDT under software control by
writing to the OPTION_REG register. Thus, time-out
periods up to 2.3 seconds can be realized.
The CLRWDT and SLEEP instructions clear the WDT
and the postscaler (if assigned to the WDT) and pre-
vent it from timing out and generating a device
RESET condition.
The TO bit in the STATUS register will be cleared upon
a WDT time-out.
Stores the W register.
Stores the STATUS register in STATUS_TEMP.
Executes the Interrupt Service Routine code.
Restores the STATUS (and bank select bit)
register.
Restores the W register.
WDT PERIOD
DD
and process variations from part to
2001 Microchip Technology Inc.