PIC18F26K22-I/ML Microchip Technology, PIC18F26K22-I/ML Datasheet - Page 111

• Manufacturer Part Number: PIC18F26K22-I/ML
• Description: IC PIC MCU 64KB FLASH 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 18Fr

Specifications of PIC18F26K22-I/ML

• Core Size: 8-Bit
• Program Memory Size: 64KB (32K x 16)
• Core Processor: PIC
• Speed: 64MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 24
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 3.8K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 19x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad
• Controller Family/series: PIC18
• No. Of I/o's: 25
• Eeprom Memory Size: 1KB
• Ram Memory Size: 3896Byte
• Cpu Speed: 64MHz
• No. Of Timers: 7
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.0
8.1
All PIC18 devices include an 8 x 8 hardware multiplier
as part of the ALU. The multiplier performs an unsigned
operation and yields a 16-bit result that is stored in the
product register pair, PRODH:PRODL. The multiplier’s
operation does not affect any flags in the STATUS
register.
Making multiplication a hardware operation allows it to
be completed in a single instruction cycle. This has the
advantages of higher computational throughput and
reduced code size for multiplication algorithms and
allows the PIC18 devices to be used in many applica-
tions previously reserved for digital signal processors.
A comparison of various hardware and software
multiply operations, along with the savings in memory
and execution time, is shown in Table .
8.2
Example 8-1 shows the instruction sequence for an 8 x 8
unsigned multiplication. Only one instruction is required
when one of the arguments is already loaded in the
WREG register.
Example 8-2 shows the sequence to do an 8 x 8 signed
multiplication. To account for the sign bits of the
arguments, each argument’s Most Significant bit (MSb)
is tested and the appropriate subtractions are done.
TABLE 8-1:
 2010 Microchip Technology Inc.
8 x 8 unsigned
8 x 8 signed
16 x 16 unsigned
16 x 16 signed
Routine
8 x 8 HARDWARE MULTIPLIER
Introduction
Operation
PERFORMANCE COMPARISON FOR VARIOUS MULTIPLY OPERATIONS
Without hardware multiply
Hardware multiply
Without hardware multiply
Hardware multiply
Without hardware multiply
Hardware multiply
Without hardware multiply
Hardware multiply
Multiply Method
Program
Memory
(Words)
Preliminary
13
33
21
28
52
35
1
6
Cycles
(Max)
242
254
69
91
28
40
EXAMPLE 8-1:
EXAMPLE 8-2:
1
6
MOVF
MULWF
MOVF
MULWF
BTFSC
SUBWF
MOVF
BTFSC
SUBWF
PIC18(L)F2X/4XK22
@ 64 MHz @ 40 MHz @ 10 MHz @ 4 MHz
62.5 ns
15.1 s
15.9 s
375 ns
4.3 s
5.7 s
1.8 s
2.5 s
ARG1, W
ARG2
ARG1, W
ARG2
ARG2, SB
PRODH, F
ARG2, W
ARG1, SB
PRODH, F
24.2 s
25.4 s
100 ns
600 ns
6.9 s
9.1 s
2.8 s
4.0 s
8 x 8 UNSIGNED
MULTIPLY ROUTINE
8 x 8 SIGNED MULTIPLY
ROUTINE
;
; ARG1 * ARG2 ->
; PRODH:PRODL
; ARG1 * ARG2 ->
; PRODH:PRODL
; Test Sign Bit
; PRODH = PRODH
;
; Test Sign Bit
; PRODH = PRODH
;
Time
102.6 s
27.6 s
36.4 s
96.8 s
16.0 s
11.2 s
400 ns
2.4 s
DS41412A-page 111
- ARG1
- ARG2
242 s
254 s
69 s
91 s
28 s
40 s
1 s
6 s