Note the following details of the code protection feature on Microchip devices:
•Microchip products meet the specification contained in their particular Microchip Data Sheet.
•Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•Microchip is willing to work with the customer who is concerned about the integrity of their code.
•Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digit al Millennium Copyright Act. If suc h a c t s
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED,
WRITTEN OR ORAL, STATUTORY OR OTHERWISE,
RELATED TO THE INFORMATION, INCLUDING BUT NOT
LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
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Microchip disclaims all liability arising from this information and
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life support systems is not authorized except with express
written approval by Microchip. No licenses are conveyed,
implicitly or otherwise, under any Microchip intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, K
EELOQ, microID, MPLAB, PIC, PICmicro, PICSTART,
PRO MATE, PowerSmart, rfPIC, and SmartShunt are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB,
PICMASTER, SEEVAL, SmartSensor and The Embedded
Control Solutions Company are registered trademarks of
Microchip Technology Incorporated in the U.S.A.
Analog-for-the-Digital Age, Application Maestro, dsPICDEM,
dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR,
FanSense, FlexROM, fuzzyLAB, In-Circuit Serial
Programming, ICSP, ICEPIC, Linear Active Thermistor,
MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM,
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All other trademarks mentioned herein are property of their
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Microchip received ISO/TS-16949:2002 quality system certification for
its worldwide headquarters, design and wafer fabrication facilities in
Chandler and Tempe, Arizona and Mountain View, California in
October 2003. The Company’s quality system processes and
procedures are for its PICmicro
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
8.0Special Feature s Of The CPU.......... .......................................... ..................... ..................... ...................................................... 35
9.0Instruction Set Summary............................................................................................................................................................ 45
11.0 Development Support.................................................................................................................................................................63
12.0 DC and AC Characteristics Graphs and Charts.........................................................................................................................67
Index .................................................................................................................................................................................................... 73
The Microchip Web Site................................... ............................................................. ....................................................................... 75
Customer Change Notification Service ................................................................................................................................................ 75
Product Identification System .............................................................................................................................................................. 77
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
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The PIC10F220/222 devices, from Microchip
Technology, are low-cost, high-performan ce, 8-b it, fully
static, Flash-based CMOS microcontrollers. They
employ a RISC architecture with only 33 single-word,
single-cycle instructions. All instructions are singlecycle (1 μs @ 4 MHz) except for prog ram branches,
which take two cycles. The PIC10F220/222 devices
deliver performance in an order of magnitude higher
than their competitors in the same price category. The
12-bit wide instructions are highly symmetrical, resulting in a typ ical 2:1 co de compre ssion over o ther 8-bi t
microcontrollers in i ts class . The easy-to-us e and easyto-remember instr ucti on se t reduc es de velop ment time
significantly.
The PIC10F220/222 products are equipped with special features that reduce system cost and power
requirements. The Power-on Reset (POR) and Device
Reset Ti mer (DR T) e limin ates the ne ed fo r the externa l
Reset circuitry. Internal Oscillator (INTOSC) mode is
provided, thereby, preserving the li mi ted num be r of I/O
pins available. Power-saving Sleep mode, Watchdog
Timer and code protection features improve system
cost, power and reliability.
The PIC10F220/222 devices are available in costeffective Flash, which is suitable for production in any
volume. The customer can take full advantage of
Microchip’s price leadership in Flash programmable
microcontrollers while benefiting from the Flash
programmable flexibility.
The PIC10F220/222 products are supported by a fullfeatured macro assembler, a software simulator, an
in-circuit debugger, a C compiler, a low-cost
development programmer and a full featured programmer. All the tools are supported on IBM
compatible machines.
®
PC and
1.1Applications
The PIC10F220/222 devices fit in applications ranging
from personal care app li anc es an d s ecu rity s yst ems to
low-power remote transmitters/receivers. The Flash
technology makes customizing application programs
(transmitter codes, appliance settings, receiver frequencies, etc.) extremely fast and convenient. The
small footprint packages, for through hole or surface
mounting, make th ese micr ocontroll ers wel l suited for
applications with space limitations. Low-cost, lowpower , high-perform ance, ease of use and I/O fl exibility
make the PIC10F220/222 devices very versatile, even
in areas where no m icrocontroller us e has been con sidered before (e.g., timer functions, logic and PLDs in
larger systems and coprocessor applications).
T ABLE 1-1:PIC10F220/222 DEVICES
ClockMaximum Frequency of Operation (MHz)88
MemoryFlash Program Memory 256512
Data Memory (bytes)1623
PeripheralsTimer Module(s)TMR0TMR0
Wake-up from Sleep on Pin ChangeYesYes
Analog Inputs22
FeaturesI/O Pins33
Input Only Pins11
Internal Pull-upsYesYes
In-Circuit Serial Programming™YesYes
Number of Instructions3333
Packages6-pin SOT-23,
Note 1:The PIC10F220/222 devices have Power-on Reset, selectable Watchdog Timer, selectable code-protect, high I/O
current capability and precision internal oscillator.
2:The PIC10F220/222 devices use serial programming with data pin GP0 and clock pin GP1.
A variety of packaging options are available. Depending on application and production requirements, the
proper device option can be selected using the
information in th is section. Wh en placing orde rs, please
use the PIC10F220/222 Product Identification System
at the back of this data s heet to s pecify the correct p art
number.
2.1Quick Turn Programming (QTP)
Devices
Microchip offers a QTP programming service for
factory production orders. This service is made
available for users who choose not to program
medium-to-high quantity units and whose code
patterns have stabilized. The devices are identical to
the Flash devices but with all Flash locations and fuse
options already programmed by the factory. Certain
code and prototype verification procedures do apply
before production shipments are available. Please
contact your loc al Microchi p Technology sales office for
more details.
PIC10F220/222
2.2Serialized Quick Turn
Programming
Microchip offers a unique programming service, where
a few user-defined locations in each device are
programmed with different serial numbers. The serial
numbers may be random, pseudo-random or
sequential.
Serial programming allows each device to have a
unique number, which can serve as an entry code,
password or ID number.
The high performance of the PIC10F220/222 devices
can be attributed to a number of architectural features
commonly found in RISC microprocessors. To begin
with, the PIC10F220/222 devices use a Harvard architecture in which program and data are accessed on
separate buses. This improves bandwidth over traditional von Neumann architectures where program and
data are fetch ed on the sa me bu s. Separating program
and data memor y further allow s instructions to be sized
differently than the 8-bit wide data word. Instruction
opcodes are 12 bit s wide, making it p ossible to have all
single-word instructions. A 12-bit wide program memory access bus fetches a 12-bit instruction in a single
cycle. A two-stage pipeline overlaps fetch and execution of instructions. Consequently, all instructions (33)
execute in a single cycle (1 μs @ 4 MHz or
500 ns @ 8 MHz) except for program branches.
The table belo w lists p rogram me mory (Flash) and data
memory (RAM) for the PIC10F220/222 devices.
Memory
Device
Program Data
PIC10F220256 x 1216 x 8
PIC10F222512 x 1223 x 8
The PIC10F220/222 devices contain an 8-bit ALU and
working register. The ALU is a general purpose arithmetic unit. It perfor ms arithmetic a nd Boolean fun ctions
between data in the working register and any register
file.
The ALU is 8 bits wide and capable of addition, subtraction, shift and logical operations. Unless otherwise
mentioned, arithmetic operations are two’s complement in nature. In two-operand instructions, one operand is typically the W (Working) register. The other
operand is either a file register or an immediate
constant. In sing le ope ran d inst ruction s, the operan d is
either the W register or a file register.
The W register is an 8-bit workin g register used for ALU
operations. It is not an addressable register.
Depending on the instruction executed, the ALU may
affect the values of the Carry (C), Digit Carry (DC) and
Zero (Z) bits in the ST ATUS register . The C and DC bits
operate as B
tively, in subtraction. See the SUBWF and ADDWF
instructions for examples.
A simplified block diagram is shown in Figure 3-1 with
the corresponding device pins described in Table 3-1.
orrow and Digit borrow out bits, respec-
The PIC10F220/222 devices can directly or indirectly
address its register files and data memory. All Special
Function Registers (SFR), including the Program
Counter (PC), are mapped in the data memory. The
PIC10F220/222 devices have a highly orthogonal
(symmetrica l) instruct ion set that m akes it possib le to
carry out any operation, on any register, using any
addressing mode. This symmetrical nature and lack of
“special optimal situ ations” make programm ing with the
PIC10F220/222 devices simple yet efficient. In
addition, the learning curve is reduced significantly.
The clock is internally divided by four to generate four
non-overlapping quadrature clocks, namely Q1, Q2,
Q3 and Q4. Internally, the PC is incremented every Q1,
and the instruction is fetched from program memory
and latched into the Instru ction Regis ter (IR) in Q4. It is
decoded and executed during Q1 through Q4. The
clocks and instruction execution flow is shown in
Figure 3-2 and Example 3-1.
FIGURE 3-2:CLOCK/INSTRUCTION CYCLE
Q2Q3Q4
OSC1
Q1
Q2
Q3
Q4
PC
Q1
PC
Q1
3.2Instruction Flow/Pipelining
An instruction cycle consists of four Q cycles (Q1, Q2,
Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the PC to change (e.g ., GOTO), t hen two c yc le s
are required to complete the ins tructi on (Exampl e 3-1).
A fetch cycle begins with the PC incrementing in Q1.
In the execution cy cle, the fetch ed instruction i s latched
into the Instr uction Regist er in cycle Q1. Th is instruction is then decoded and executed during the Q2, Q3
and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
Q2Q3Q4
PC + 1PC + 2
Q2Q3Q4
Q1
Internal
Phase
Clock
Fetch INST (PC)
Execute INST (PC - 1)
Fetch INST (PC + 1)
Execute INST (PC)
Fetch INST (PC + 2)
Execute INST (PC + 1)
EXAMPLE 3-1:INSTRUCTION PIPELINE FLOW
1. MOVLW 03H
2. MOVWF GPIO
3. CALL SUB_1
4. BSF GPIO, BIT1
All instructions are si ngle cycle, except for any program bra nches. These tak e two cycles, since th e fetch instruction
is “flushed” from the pipeline, while the new instruction is being fetched and then executed.
The PIC10F220/222 memories are organized into program memory and data memory. Data memory banks
are accessed using the File Select Register (FSR).
4.1Program Memory Organization for
the PIC10F220
The PIC10F220 devices hav e a 9-bit Prog ram Coun ter
(PC) capable of addressing a 512 x 12 program
memory space.
Only the first 256 x 12 (0000h-00FFh) for the
PIC10F220 are physically implemented (see
Figure 4-1). Accessing a location above these
boundaries will cause a wraparound within the first
256 x 12 space (PIC10F220). The effective Reset
vector is at 0000h, (see Figure 4-1). Location 00FF h
(PIC10F220) contains the internal clock oscillator
calibration value. This value should never be
overwritten.
FIGURE 4-1:PROGRAM MEMORY MAP
AND STACK FOR THE
PIC10F220
PC<7:0>
CALL, RETLW
Stack Level 1
Stack Level 2
<8:0>
9
4.2Program Memory Organization for
the PIC10F222
The PIC10F222 devices have a 10-bit Program
Counter (PC) capable of addressing a 1024 x 12
program memory space.
Only the first 512 x 12 (0000h-01FFh) for the MemHigh are physically implemented (see Figure 4-2).
Accessing a location above these boundaries will
cause a wraparound within the first 512 x 12 space
(PIC10F222). The effective Reset vector is at 0000h
(see Figure 4-2). Location 01FFh (PIC10F222) contains the internal clock oscillator calibration value.
This value should never be overwritt en.
FIGURE 4-2:PROGRAM MEMORY MAP
AND STACK FOR THE
PIC10F222
<9:0>
10
0000h
CALL, RETLW
PC<8:0>
Stack Level 1
Stack Level 2
Reset Vector
On-Chip Program
Memory
(1)
Reset Vector
On-chip Program
Memory
Space
User Memory
256 Word
Note 1:Address 0000h becomes the
effective Reset vector. Location 00FFh
contains the MOVLW xx internal oscillator
calibration value.
(1)
0000h
00FFh
0100h
01FFh
Space
User Memory
512 Words
Note 1:Address 0000h becomes the effective
Reset vector. Location 01FFh contains the
MOVLW xx internal oscillator calibration
value.
Data memory is composed of registers or bytes of
RAM. Therefore, d ata memory for a device is sp ec ifie d
by its register file. The register file is divided into two
functional groups: Special Function Registers (SFR)
and General Purpose Registers (GPR).
The Special Function Reg ist ers incl ude the TM R0 register, the Program Counter (PC), the STATUS register,
the I/O register (GPIO) and the File Select Register
(FSR). In addition, Speci al Function Registe rs are used
to control the I/O port configuration and prescaler
options.
The General Purpose Registers are used for data and
control information under com mand of the instructions .
For the PIC10F220, the register file is composed of
9 Special Function Registers and 16 General Purpose
Registers (Figure 4-3, Figure 4-4).
For the PIC10F222, the register file is composed of
9 Special Function Registers and 23 General Purpose
Registers (Figure 4-4).
4.3.1GENERAL PURPOSE REGISTER
FILE
The General Purpos e Registe r file i s accessed , eithe r
directly o r indirectly, through the F ile Select Regist er
(FSR). See Section 4.9 “Indirect Data Addressing;
INDF and FSR Registers”.
FIGURE 4-4:PIC10F222 REGISTER
FILE MAP
File Address
(1)
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
1Fh
Note 1: Not a physical register. See Section 4.9
“Indirect Data Addressing; INDF and
FSR Registers”.
INDF
TMR0
PCL
STATUS
FSR
OSCCAL
GPIO
ADCON0
ADRES
General
Purpose
Registers
FIGURE 4-3:PIC10F220 REGIST E R
FILE MAP
File Address
(1)
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
0Fh
10h
1Fh
Note 1: Not a physical register. See Section 4.9
“Indirect Data Addressing; INDF and
FSR Registers”.
The Special Function Registers (SFRs) are registers
used by the CPU and per ipheral functio ns to con trol the
operation of the device (Table 4-1).
The Special Function Registers can be classified into
two sets. The Special Function Registers associated
with the “core” functions are described in this section.
Those related to the operation of the peripheral
features are described in the section for each
peripheral feature.
TABLE 4-1:SPECIAL FUNCTION REGISTER (SFR) SUMMARY
AddressNameBit 7Bit 6Bit 5Bit 4Bit 3Bit 2 Bit 1Bit 0
00hINDFUses contents of FSR to address data memory (not a physical register)xxxx xxxx22
01hTMR08-bit Real-Time Clock/Counterxxxx xxxx27
02hPCL
07hADCON0ANS1ANS0
08hADRESResult of Analog-to-Digital Conversionxxxx xxxx32
N/ATRISGPIO
N/AOPTIONGPWU
Legend:— = unimplemented, read as ‘0’, x = unknown, u = unchanged.
Note 1:The upper byte of the Program Counter is not directly accessible. See S ecti on 4.7 “Program Counter” for an
(1)
Low-Order 8 bits of PC1111 111121
——TOPDZDCC0--1 1xxx
————GP3GP2GP1GP0---- xxxx23
——CHS1CHS0 GO/DONEADON11-- 110032
————I/O Control Register---- 111123
GPPUT0CST0SEPSAPS2PS1PS01111 111119
explanation of how to access these bits.
2:Other (non power-up) Resets include external Reset through MCLR
This register contains the arithmetic status of the ALU,
the Reset status and the page preselect bit.
The STATUS register can be the destination for any
instruction, as with any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bit s are set or cleared ac cording to the
device logic. Furthermore, the TO
writable. Therefore, the result of an instruction with the
STATUS register as the destination may be different
than intended.
and PD bits are not
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as 000u u1uu (where u = unchanged).
Therefore, it is recommended that only BCF, BSF andMOVWF instructions be used to alter the STATUS register. The se in structions do not affect the Z, DC or C bits
from the ST A TUS reg ister . For other instructio ns, which
do affect STATUS bits, see Section 9.0 “Instruction
Set Summary”.
REGISTER 4-1:STATUS REGISTER (ADDRESS: 03h)
R/W-0R/W-0R/W-0R-1R-1R/W-xR/W-xR/W-x
GPWUF
bit 7bit 0
bit 7GPWUF: GPIO Reset bit
1 = Reset due to wake-up from Sleep on pin change
0 = After power-up or other Reset
bit 6-5Reserved: Do not use. Use of this bit may affect upward compatibility with future products.
bit 4TO
bit 3PD
bit 2Z: Zero bit
bit 1DC: Digit Carry/Bo
bit 0C: Carry/borrow
: Time-out bit
1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
: Power-Down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
ADDWF
1 = A carry to the 4th low-order bit of the result occurred
0 = A carry to the 4th low-order bit of the result did not occur
SUBWF:
1 = A borrow from the 4th low-order bit of the result did not occur
0 = A borrow from the 4th low-order bit of the result occurred
ADDWF
1 = A carry occurred1 = A borrow did not occur Load bit with LSb or MSb, respectively
0 = A carry did not occur0 = A borrow occurred
:
:SUBWF:RRF or RLF:
——TO PDZDCC
rrow bit (for ADDWF and SUBWF instructions)
bit (for ADDWF, SUBWF and RRF, RLF instructions)
Legend:
R = Readable bitW = Writable bitU = Unimplemented bit, read as ‘0’
-n = Value at POR‘1’ = Bit is set‘0’ = Bit is clearedx = Bit is unknown
The OPTION re gister is a 8-bit wid e, write-only register ,
which contains various control bits to configure the
Timer0/WDT prescaler and Timer0.
The OPTION register is not memory mapped and is
therefore only addressable by executing the OPTION
instruction. The cont ent s of the W re gister w ill be tran sferred to the OPTION register. A Reset sets the
OPTION<7:0> bits.
REGISTER 4-2:OPTION REGISTER (PIC10F220/222)
W-1W-1W-1W-1W-1W-1W-1W-1
GPWU
bit 7bit 0
GPPUT0CST0SEPSAPS2PS1PS0
PIC10F220/222
Note 1: If TRIS bit is set to ‘0’, the wake-up on
change and pull-up functions are disabled for that pin (i.e., note that TRIS
overrides Option control of GPPU
GPWU)
2: If the T0CS bit is set to ‘1’, it w i ll ov er r ide
the TRIS function on the T0CKI pin.
.
and
bit 7GPWU
bit 6GPPU
bit 5T0CS: Timer0 Clock Source Select bit
bit 4T0SE: Timer0 Source Edge Select bit
bit 3PSA: Prescaler Assignment bit
bit 2-0PS<2:0>: Prescaler Rate Select bits
: Enable Wake-up on Pin Change bit (GP0, GP1, GP3)
1 = Disabled
0 = Enabled
: Enable Weak Pull-ups bit (GP0, GP1, GP3)
1 = Disabled
0 = Enabled
1 = Transition on T0CKI pin (overrides TRIS on the T0CKI pin)
0 = Transition on internal instruction cycle clock, F
1 = Increment on high-to-low transition on the T0CKI pin
0 = Increment on low-to-high transition on the T0CKI pin
1 = Prescaler assigned to the WDT
0 = Prescaler assigned to Timer0
The Oscillator Calibrati on (OSCCAL) register is used to
calibrate the internal precision 4/8 MHz oscillator. It
contains seven bit s for cal ibra tio n
Note:Erasing the device will also erase the pre-
programmed internal calibration value for
the internal oscillator. The calibration
value must be read prior to erasing the
part so it can be reprogrammed correctly
later.
After you move in the calibration constant, do not
change the value. See Section 8.2.2 “Internal 4/8 MHz
As a program instruction is executed, the Program
Counter (PC) will contain the address of the next
program instruction to be executed. The PC value is
increased by one every instruction cycle, unless an
instruction changes the PC.
For a GOTO instruction, bits 8:0 of the PC are provided
by the GOTO inst ruction word . The PC Latch (P CL) is
mapped to PC<7:0>.
For a CALL instruction, or any instruction where the
PCL is the destinatio n, bits 7:0 of the PC ag ain are pr ovided by the instruction word. However, PC<8> does
not come from the instruction word, but is always
cleared (Figure 4-5).
Instructions wh ere the PCL is th e destinatio n, or modif y
PCL instructi ons, incl ude MOVWF PC, ADDWF PC and
BSF PC, 5.
Note:Because PC<8> is cleared in the CALL
instruction or any modify PCL instructi on,
all subroutine calls or computed jumps are
limited to the first 256 locations of any
program me mory page ( 512 words long).
FIGURE 4-5:LOADING OF PC
BRANCH INSTRUCTIONS
GOTO Instruction
870
PC
Instruction Word
PCL
4.7.1EFFECTS OF RESET
The PC is set upon a Reset, which means that the PC
addresses the last location in program memory (i.e.,
the oscillator calibration instruction). After executing
MOVLW xx, the PC will roll over to location 0000h and
begin executing user code.
4.8Stack
The PIC10F220 device has a 2-deep, 8-bit wide
hardware PUSH/POP stack.
The PIC10F222 device has a 2-deep, 9-bit wide
hardware PUSH/POP stack.
A CALL instruction will PUSH the current value of
stack 1 into stack 2 and then PUSH the current PC
value, incremented by one, into stack level 1. If more
than two sequential CALLs are exec uted, onl y the most
recent two return addresses are stored.
A RETLW instruction will POP the contents of stack
level 1 into the PC an d then copy st ack l evel 2 cont ent s
into level 1. If more than two sequential RETLWs are
executed, the stack will be filled with the address
previously stored in level 2.
Note 1: The W register will be loaded with the lit-
eral value spec ified in the ins truction. This
is particularly useful for the implementation of data look-up tables within the
program memory.
2: There are no Status bits to indicate stack
overflows or stack underflow conditions.
3: There are no instructions mnemonics
called PUSH or POP. These are actions
that occur from the e xecution of the CALL
and RETLW instructions.
The INDF register is not a physi cal register. Addressing
INDF actually address es the reg ister whos e addres s is
contained in the FSR regis ter (FSR is a pointer). This is
Indirect A ddressing mode.
4.9.1INDIRECT ADDRESSING
• Register file 09 contains the value 10h.
• Register file 0A contains the value 0Ah.
• Load the value 09 into the FSR register.
• A read of the INDF register will return the value
of 10h.
• Increment the value of the FSR register by one
(FSR = 0A).
• A read of the INDR register now will return the
value of 0Ah.
Reading INDF itself indirectly (FSR = 0) will produce
00h. Writing to the INDF register indirectly results in a
no operation (although Status bits may be affected).
A simple program to clear RAM locations 10h-1Fh
using Indirect Addressing is shown in Example 4-1.
FIGURE 4-6:DIRECT/INDIRECT ADDRESSING
EXAMPLE 4-1:HOW TO CLEAR RAM
USING INDIRECT
ADDRESSING
MOVLW0x10;initialize pointer
MOVWFFSR;to RAM
NEXTCLRFINDF;clear INDF
;register
INCFFSR, F ;inc pointer
BTFSCFSR, 4 ;all done?
GOTONEXT;NO, clear next
CONTINUE
:;YES, continue
:
The FSR is a 5-bit wide register. It is used in conjunction with the INDF regis ter to indirectly a ddress the dat a
memory area.
The FSR<4:0> bits are used to select data memory
addresses 00h to 1Fh.
Note:The 10F220 and 10F222 do not use
banking. FSR<7:5> are unimplemented
and read as ‘1’s.
Direct Addressing
(opcode)04
Location Select
00h
Data
Memory
Note 1: For register map detail, see Section 4.3 “D ata Memory Organization”.
As with any other register, the I/O register(s) can be
written and read under pro gram contro l. However, read
instructions (e.g., MOVF GPIO, W) always read the I/O
pins independent of the pin’s Input/Output modes. On
Reset, all I/O ports are defined as input (inputs are at
high-impedance) since the I/O control registers are all
set.
5.1GPIO
GPIO is an 8-bit I/O register. Only the low-order 4 bits
are used (GP<3:0>). Bits 7 through 4 are unimplemented and read as ‘0’s. Please note that GP3 is an
input only pin. Pins GP0, GP1 and GP3 can be configured with weak pull-ups and also for wake-up on
change. The wake-up on change and weak pull-up
functions are not individu al ly pin sele ct able. If
GP3/MCLR
be enabled via the Configuration Word. Configuring
GP3 as MCLR
function for this pin.
5.2TRIS Registers
The Output Driver Control register is loaded with the
contents of the W register by executing the TRIS f
instruction. A ‘1’ from a TRIS register bi t puts the corresponding output driver in a high-impe dance mod e. A ‘0’
puts the contents of the output data latch on the
selected pins, enabling the outp ut buffer. The
exceptions are GP3, which is input only, and the
GP2/T0CKI/FOSC4 pin, which may be controlled by
various registers. See Table5-1.
Note:A read of the ports reads the pins, not the
is configured as MCLR, a weak pull-up can
disables the wake-up on change
output data latches. That is, if an output
driver on a pin is enab led and driv en high,
but the external system is holding it low, a
read of the port will indicate that the pin is
low.
The TRIS registers are “write-only” and are set (output
drivers disabled) upon Re se t.
5.3I/O Interfacing
The equivalent circuit for an I/O port pin is shown in
Figure 5-5. All port pins, except GP3, which is input
only , ma y be used for both in put and out put operati ons.
For input operations , the se ports are non-latching. Any
input must be present until read by an input instruction
(e.g., MOVF GPIO, W). The outputs are latched and
remain unchanged unt il t he outp ut latc h is rewri tten. To
use a port pin as output, the corresponding direction
control bit in TRIS must be cleared (= 0). For use as an
input, the corresponding TRIS bit must be set. Any I/O
pin (except GP3) can be programmed individually as
input or output.
FIGURE 5-1:EQUIVALENT CIRCUIT
FOR A SINGLE I/O PIN
Data
Bus
WR
Port
W
Reg
TRIS ‘f’
Note 1: See Table 3-1 for buffer type.
D
D
Data
Latch
CK
TRIS
Latch
CK
Reset
Q
VDD
VDD
Q
Q
Q
RD Port
P
N
SS
V
(1)
I/O
pin
VSS
TABLE 5-1:ORDER OF PRECEDENCE FOR PIN FUNCTIONS
PriorityGP0GP1GP2GP3
1AN0AN1FOSC4I/MCLR
2TRIS GPIOTRIS GPIOT0CKI—
3
——TRIS GPIO—
TABLE 5-2:REQUIREMENTS TO MAKE PINS AVAILABLE IN DIGITAL MODE
FOSC4T0CSANS1ANS0MCLR E
RegisterOSCCALOPTIONADCON0ADCON0CONFIG
GP0
GP1
GP200
GP3
Legend:— = Condition of bit will have no effect on the setting of the pin to digital mode.