PIC16F1937-I/P Microchip Technology, PIC16F1937-I/P Datasheet - Page 14

• Manufacturer Part Number: PIC16F1937-I/P
• Description: IC PIC MCU FLASH 512KX14 40-PDIP
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F1937-I/P

• Program Memory Type: FLASH
• Program Memory Size: 14KB (8K x 14)
• Package / Case: 40-DIP (0.600", 15.24mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 32MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 36
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 14x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: EUSART/MI2C/SPI
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 5
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 14-ch x 10-bit
• A/d Bit Size: 10 bit
• A/d Channels Available: 14
• Height: 4.95 mm
• Length: 53.21 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 1.8 V
• Width: 14.73 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Notice that the Arithmetic_left_shift and the
logical_left_shift are identical functions. The
enhanced
logical_left_shift
substitute the logical_left_shift if ASLF is used
in the assembly language.
TABLE 5:
Table 5 above shows the differences between the
different shift operations.
MULTI-BYTE SHIFTS
A multi-byte shift can be created simply by making the
first operation the new shift instruction and all
subsequent operations rotate. The new instructions
shift the outgoing bit into the Carry flag where the rotate
instruction will bring it into the next byte.
ROM Table Access
Accessing data tables is frequently performed in many
applications. The traditional method on a PIC12/16
device is to assemble the table into a series of RETLW
instructions. By adding a value to the PC a value at a
specific offset can be returned to the calling function.
The enhanced PIC12/16 has a few improvements.
DS41375A-page 14
LSRF
LSLF
ASLF
ASRF_16
Starting Value
0x7F
0x7F
0x7F
0x80
0x80
0x80
val,f ; logical right shift
val,f ; logical left shift
val,f ; Arithmetic left shift
PIC12/16
SHIFT OPERATION
DIFFERENCES
ASRF
RRF
; really
LSRF/ASLF
LSRF/ASLF
LSRF/ASLF
LSRF/ASLF
shift)
Operation
ASRF
ASRF
but
only
MSB_f
LSB_f
the
logical
provides
assembler
0xC0, C = 0
0xFE, C = 0
0x00, C = 1
0x40, C = 0
0x3F, C = 1
0x3F, C = 1
Final Value
left
the
will
Fast Tables with FSR
The first trick is to simply use the FSR/INDF to return
values saved in program memory. When the MSB is set
in the FSRnH register, the value returned by INDF is
the Least Significant Byte (LSB) in the program
memory address specified by the FSR register. By
using the FSR to point to data in the program memory,
the additional capabilities of the MOVIW and MOVWI
instruction can be used to keep the software short.
Generally, the setup to use the FSR takes 4 cycles,
while each fetch can take 2 because fetches to
program memory take an extra cycle. The primary
advantage to using the FSR to fetch data from program
memory is the unified pointer. Data can be located in
GPR or program memory with no change in the access
requirements.
code
data_table
Note:
RETLW
RETLW
RETLW
RETLW
RETLW
RETLW
RETLW
MOVLW
MOVWF
MOVLW
ADDWF
MOVWF
CLRW
ADDWFC
MOVF
The HIGH directive will automatically set
the MSB if the label references an address
in program memory.
‘a’
‘m’
‘y’
‘ ‘
‘d’
‘a’
‘t’
HIGH data_table
FSROH
LOW data_table
data_index
FSR0L
FSR0H
INDF0, W
© 2009 Microchip Technology Inc.