PIC18C442-I/P Microchip Technology, PIC18C442-I/P Datasheet - Page 63

• Manufacturer Part Number: PIC18C442-I/P
• Description: IC MCU OTP 8KX16 A/D 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C442-I/P

• Core Size: 8-Bit
• Program Memory Size: 16KB (8K x 16)
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 33
• Program Memory Type: OTP
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC18
• No. Of I/o's: 34
• Ram Memory Size: 512Byte
• Cpu Speed: 40MHz
• No. Of Timers: 4
• Processor Series: PIC18C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: MSSP, SPI, I2C, PSP, USART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 34
• Number Of Timers: 1 x 16 bit
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: ICE2000, DM163022, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: I3DB18C452 - BOARD DAUGHTER ICEPIC3444-1001 - DEMO BOARD FOR PICMICRO MCU
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

6.0
6.1
An 8 x 8 hardware multiplier is included in the ALU of
the PIC18CXX2 devices. By making the multiply a
hardware operation, it completes in a single instruction
cycle. This is an unsigned multiply that gives a 16-bit
result. The result is stored into the 16-bit product regis-
ter pair (PRODH:PRODL). The multiplier does not
affect any flags in the ALUSTA register.
TABLE 6-1:
6.2
Example 6-1 shows the sequence to do an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
Example 6-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s Most Significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 6-1:
MOVF
MULWF
16 x 16 unsigned
2001 Microchip Technology Inc.
8 x 8 unsigned
16 x 16 signed
8 x 8 signed
Routine
8 X 8 HARDWARE MULTIPLIER
Introduction
Operation
ARG1, W
ARG2
PERFORMANCE COMPARISON
8 x 8 UNSIGNED
MULTIPLY ROUTINE
Without hardware multiply
Without hardware multiply
Without hardware multiply
Without hardware multiply
;
; ARG1 * ARG2 ->
;
Hardware multiply
Hardware multiply
Hardware multiply
Hardware multiply
Multiply Method
PRODH:PRODL
Program
Memory
(Words)
13
33
21
24
52
36
1
6
Making the 8 x 8 multiplier execute in a single cycle
gives the following advantages:
• Higher computational throughput
• Reduces code size requirements for multiply
The performance increase allows the device to be used
in applications previously reserved for Digital Signal
Processors.
Table 6-1 shows a performance comparison between
enhanced devices using the single cycle hardware mul-
tiply, and performing the same function without the
hardware multiply.
EXAMPLE 6-2:
Example 6-3 shows the sequence to do a 16 x 16
unsigned multiply. Equation 6-1 shows the algorithm
that is used. The 32-bit result is stored in four registers,
RES3:RES0.
EQUATION 6-1:
RES3:RES0
MOVF
MULWF
BTFSC
SUBWF
MOVF
BTFSC
SUBWF
algorithms
Cycles
(Max)
242
254
69
91
24
36
1
6
ARG1,
ARG2
ARG2,
PRODH, F
ARG2,
ARG1,
PRODH, F
=
=
@ 40 MHz
ARG1H:ARG1L
(ARG1H
(ARG1H
(ARG1L
(ARG1L
24.2 s
25.4 s
100 ns
600 ns
6.9 s
9.1 s
2.4 s
3.6 s
SB
SB
W
W
8 x 8 SIGNED MULTIPLY
ROUTINE
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
PIC18CXX2
; ARG1 * ARG2 ->
; PRODH:PRODL
; Test Sign Bit
; PRODH = PRODH
;
; Test Sign Bit
; PRODH = PRODH
;
ARG2H
ARG2L
ARG2H
ARG2L)
@ 10 MHz
102.6 s
27.6 s
36.4 s
96.8 s
14.4 s
Time
400 ns
2.4 s
9.6 s
ARG2H:ARG2L
DS39026C-page 61
2
2
2
- ARG1
- ARG2
16
8
8
)+
)+
)+
@ 4 MHz
242 s
254 s
69 s
91 s
24 s
36 s
1 s
6 s