PIC16F636-I/P Microchip Technology Inc., PIC16F636-I/P Datasheet - Page 29

• Manufacturer Part Number: PIC16F636-I/P
• Description: 14 PIN, 3.5 KB FLASH, 128 RAM, 12 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F636-I/P

• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 12
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 14-pin PDIP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 1-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

2.4
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
actually 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 and the IRP bit
(STATUS<7>), as shown in Figure 2-6.
FIGURE 2-6:
© 2005 Microchip Technology Inc.
Bank Select
RP1 RP0
Note: For memory map detail, see Figure 2-2.
Indirect Addressing, INDF and
FSR Registers
Direct Addressing
6
Data
Memory
Location Select
DIRECT/INDIRECT ADDRESSING PIC12F635/PIC16F636/639
From Opcode
7Fh
00h
Bank 0
00
0
Bank 1
01
PIC12F635/PIC16F636/639
Preliminary
Bank 2
10
A simple program to clear RAM location 20h-2Fh using
indirect addressing is shown in Example 2-1.
EXAMPLE 2-1:
NEXT
CONTINUE
Bank 3
11
MOVLW
MOVWF
CLRF
INCF
BTFSS
GOTO
IRP
Bank Select
180h
1FFh
0x20
FSR
INDF
FSR
FSR,4
NEXT
7
Indirect Addressing
INDIRECT ADDRESSING
File Select Register
;initialize pointer
;to RAM
;clear INDF register
;INC POINTER
;all done?
;no clear next
;yes continue
DS41232B-page 27
Location Select
0