PIC16F1938-I/ML Microchip Technology, PIC16F1938-I/ML Datasheet - Page 25

• Manufacturer Part Number: PIC16F1938-I/ML
• Description: IC MCU 8BIT FLASH 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F1938-I/ML

• Core Size: 8-Bit
• Program Memory Size: 28KB (16K x 14)
• Oscillator Type: Internal
• Core Processor: PIC
• Speed: 32MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Controller Family/series: PIC16F
• No. Of I/o's: 25
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 1024Byte
• Cpu Speed: 32MHz
• Package: 28QFN EP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 32 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 25
• Interface Type: I2C/SPI/USART
• On-chip Adc: 11-chx10-bit
• Number Of Timers: 5
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

FIGURE 2-3:
© 2009 Microchip Technology Inc.
Program
Memory
On-chip
INTERRUPT, RETFIE
RETURN, RETLW
CALL, CALLW
Rollover to Page 0
Rollover to Page 7
Interrupt Vector
Stack Level 15
Stack Level 0
Stack Level 1
Reset Vector
PROGRAM MEMORY MAP
AND STACK FOR THE
PIC16F1938/PIC16LF1938/
PIC16F1939/PIC16LF1939
PC<14:0>
Page 1
Page 2
Page 3
Page 4
Page 7
Page 0
15
0000h
0004h
0005h
7FFFh
07FFh
0800h
0FFFh
1000h
17FFh
1800h
1FFFh
2000h
3FFFh
4000h
Preliminary
2.1.1
There are two methods of accessing constants in pro-
gram memory. The first method is to use tables of
RETLW instructions. The second method is to set an
FSR to point to the program memory.
2.1.1.1
The RETLW instruction can be used to provide access
to tables of constants. The recommended way to create
such a table is shown in Example 2-1.
EXAMPLE 2-1:
The BRW instruction makes this type of table very sim-
ple to implement. If your code must remain portable
with previous generations of microcontrollers, then the
BRW instruction is not available so the older table read
method must be used.
2.1.1.2
The program memory can be accessed as data by set-
ting bit 7 of the FSRxH register and reading the match-
ing INDFx register. The MOVIW instruction will place the
lower 8 bits of the addressed word in the W register.
Writes to the program memory cannot be performed via
the INDF registers. Instructions that access the pro-
gram memory via the FSR require one extra instruction
cycle to complete. Example 2-2 demonstrates access-
ing the program memory via an FSR.
EXAMPLE 2-2:
constants
my_function
bsf FSR1H,7
moviw 0[INDF1]
;THE PROGRAM MEMORY IS IN W
PIC16F193X/LF193X
brw
retlw DATA1
retlw DATA2
retlw DATA3
retlw DATA4
;… LOTS OF CODE…
movlw
call constants
;… THE CONSTANT IS IN W
READING PROGRAM MEMORY AS
DATA
RETLW Instruction
Indirect Read with FSR
DATA_INDEX
RETLW INSTRUCTION
ACCESSING PROGRAM
MEMORY VIA FSR
DS41364C-page 25