PIC16F628-20/P Microchip Technology, PIC16F628-20/P Datasheet - Page 27
![IC MCU FLASH 2KX14 COMP 18DIP](/photos/6/76/67657/18-dip_300mil__sml.jpg)
PIC16F628-20/P
Manufacturer Part Number
PIC16F628-20/P
Description
IC MCU FLASH 2KX14 COMP 18DIP
Manufacturer
Microchip Technology
Series
PIC® 16Fr
Datasheet
1.PIC16F627-04P.pdf
(170 pages)
Specifications of PIC16F628-20/P
Program Memory Type
FLASH
Program Memory Size
3.5KB (2K x 14)
Package / Case
18-DIP (0.300", 7.62mm)
Core Processor
PIC
Core Size
8-Bit
Speed
20MHz
Connectivity
UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
16
Eeprom Size
128 x 8
Ram Size
224 x 8
Voltage - Supply (vcc/vdd)
3 V ~ 5.5 V
Oscillator Type
Internal
Operating Temperature
0°C ~ 70°C
Processor Series
PIC16F
Core
PIC
Data Bus Width
8 bit
Data Ram Size
224 B
Interface Type
SCI/USART
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
16
Number Of Timers
3
Operating Supply Voltage
3 V to 5.5 V
Maximum Operating Temperature
+ 70 C
Mounting Style
Through Hole
3rd Party Development Tools
52715-96, 52716-328, 52717-734
Development Tools By Supplier
PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
Minimum Operating Temperature
0 C
Data Rom Size
128 B
Height
3.3 mm
Length
22.86 mm
Supply Voltage (max)
5.5 V
Supply Voltage (min)
3 V
Width
6.35 mm
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
DVA16XP183 - ADAPTER ICE 18DIP/SOIC/SSOPAC164010 - MODULE SKT PROMATEII DIP/SOIC
Data Converters
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
3.3
The program counter (PC) is 13-bits wide. The low byte
comes from the PCL register, which is a readable and
writable register. The high byte (PC<12:8>) is not
directly readable or writable and comes from PCLATH.
On any RESET, the PC is cleared. Figure 3-3 shows
the two situations for the loading of the PC. The upper
example in the figure shows how the PC is loaded on a
write to PCL (PCLATH<4:0> → PCH). The lower exam-
ple in the figure shows how the PC is loaded during a
CALL or GOTO instruction (PCLATH<4:3> → PCH).
FIGURE 3-3:
3.3.1
A computed GOTO is accomplished by adding an offset
to the program counter (ADDWF PCL). When doing a
table read using a computed GOTO method, care
should be exercised if the table location crosses a PCL
memory boundary (each 256 byte block). Refer to the
application note “Implementing a Table Read” (AN556).
3.3.2
The PIC16F62X family has an 8-level deep x 13-bit
wide hardware stack (Figure 3-1 and Figure 3-2). The
stack space is not part of either program or data space
and the stack pointer is not readable or writable. The
PC is PUSHed onto the stack when a CALL instruction
is executed or an interrupt causes a branch. The stack
is POPed in the event of a RETURN,
RETFIE instruction execution. PCLATH is not affected
by a PUSH or POP operation.
2003 Microchip Technology Inc.
PC
PC
12
12
2
PCL and PCLATH
11 10
5
PCH
PCLATH<4:3>
PCH
COMPUTED GOTO
STACK
PCLATH
PCLATH<4:0>
8
PCLATH
8
7
7
LOADING OF PC IN
DIFFERENT SITUATIONS
PCL
PCL
11
8
0
0
Instruction with
PCL as
Destination
ALU result
GOTO, CALL
Opcode <10:0>
RETLW or a
Preliminary
The stack operates as a circular buffer. This means that
after the stack has been PUSHed eight times, the ninth
push overwrites the value that was stored from the first
push. The tenth push overwrites the second push (and
so on).
3.4
The INDF register is not a physical register. Addressing
the INDF register will cause indirect addressing.
Indirect addressing is possible by using the INDF
register. Any instruction using the INDF register actu-
ally accesses data pointed to by the file select register
(FSR). Reading INDF itself indirectly will produce 00h.
Writing to the INDF register indirectly results in a no-
operation (although STATUS bits may be affected). An
effective 9-bit address is obtained by concatenating the
8-bit FSR register and the IRP bit (STATUS<7>), as
shown in Figure 3-4.
A simple program to clear RAM location 20h-2Fh using
indirect addressing is shown in Example 3-1.
EXAMPLE 3-1:
NEXT
Note 1: There are no STATUS bits to indicate
Indirect Addressing, INDF and
FSR Registers
2: There are no instructions/mnemonics
movlw
movwf
clrf
incf
btfss
goto
stack
conditions.
called PUSH or POP. These are actions
that occur from the execution of the
CALL, RETURN, RETLW and RETFIE
instructions, or the vectoring to an
interrupt address.
overflow
0x20
FSR
INDF
FSR
FSR,4
NEXT
Indirect Addressing
PIC16F62X
;initialize pointer
;to RAM
;clear INDF register
;inc pointer
;all done?
;no clear next
;yes continue
or
stack
DS40300C-page 25
underflow