PIC16F726-E/SO Microchip Technology, PIC16F726-E/SO Datasheet - Page 147

• Manufacturer Part Number: PIC16F726-E/SO
• Description: 14KB Flash Program, 1.8V-5.5V, 16MHz Internal Oscillator, 8b ADC, CCP, I2C/SPI,
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F726-E/SO

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 14KB (8K x 14)
• Program Memory Type: FLASH
• Ram Size: 368 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 11x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 28-SOIC (7.5mm Width)
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 368 B
• Interface Type: I2C, SCI, SPI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 25
• Number Of Timers: 3
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 11 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164112 - VOLTAGE LIMITER MPLAB ICD2 VPPICE2000 - EMULATOR MPLAB-ICE 2000 POD
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

16.1
The AUSART transmits and receives data using the
standard non-return-to-zero (NRZ) format. NRZ is
implemented with two levels: a V
represents a ‘1’ data bit, and a V
represents a ‘0’ data bit. NRZ refers to the fact that
consecutively transmitted data bits of the same value
stay at the output level of that bit without returning to a
neutral level between each bit transmission. An NRZ
transmission port idles in the mark state. Each character
transmission consists of one Start bit followed by eight
or nine data bits and is always terminated by one or
more Stop bits. The Start bit is always a space and the
Stop bits are always marks. The most common data
format is 8 bits. Each transmitted bit persists for a period
of 1/(Baud Rate). An on-chip dedicated 8-bit Baud Rate
Generator is used to derive standard baud rate
frequencies from the system oscillator. Refer to
Table 16-5 for examples of baud rate configurations.
The AUSART transmits and receives the LSb first. The
AUSART’s transmitter and receiver are functionally
independent, but share the same data format and baud
rate. Parity is not supported by the hardware, but can
be implemented in software and stored as the ninth
data bit.
16.1.1
The AUSART transmitter block diagram is shown in
Figure 16-1. The heart of the transmitter is the serial
Transmit Shift Register (TSR), which is not directly
accessible by software. The TSR obtains its data from
the transmit buffer, which is the TXREG register.
16.1.1.1
The AUSART transmitter is enabled for asynchronous
operations by configuring the following three control
bits:
• TXEN = 1
• SYNC = 0
• SPEN = 1
All other AUSART control bits are assumed to be in
their default state.
Setting the TXEN bit of the TXSTA register enables the
transmitter circuitry of the AUSART. Clearing the SYNC
bit of the TXSTA register configures the AUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA
automatically configures the TX/CK I/O pin as an output.
© 2009 Microchip Technology Inc.
AUSART Asynchronous Mode
register
AUSART ASYNCHRONOUS
TRANSMITTER
Enabling the Transmitter
enables
the
OL
OH
space state which
mark state which
AUSART
and
PIC16F72X/PIC16LF72X
16.1.1.2
A transmission is initiated by writing a character to the
TXREG register. If this is the first character, or the
previous character has been completely flushed from
the TSR, the data in the TXREG is immediately
transferred to the TSR register. If the TSR still contains
all or part of a previous character, the new character
data is held in the TXREG until the Stop bit of the
previous character has been transmitted. The pending
character in the TXREG is then transferred to the TSR
in one T
transmission. The transmission of the Start bit, data bits
and Stop bit sequence commences immediately
following the transfer of the data to the TSR from the
TXREG.
16.1.1.3
The TXIF interrupt flag bit of the PIR1 register is set
whenever the AUSART transmitter is enabled and no
character is being held for transmission in the TXREG.
In other words, the TXIF bit is only clear when the TSR
is busy with a character and a new character has been
queued for transmission in the TXREG. The TXIF flag
bit is not cleared immediately upon writing TXREG.
TXIF becomes valid in the second instruction cycle
following the write execution. Polling TXIF immediately
following the TXREG write will return invalid results. The
TXIF bit is read-only, it cannot be set or cleared by
software.
The TXIF interrupt can be enabled by setting the TXIE
interrupt enable bit of the PIE1 register. However, the
TXIF flag bit will be set whenever the TXREG is empty,
regardless of the state of TXIE enable bit.
To use interrupts when transmitting data, set the TXIE
bit only when there is more data to send. Clear the
TXIE interrupt enable bit upon writing the last character
of the transmission to the TXREG.
Note 1: When the SPEN bit is set the RX/DT I/O pin
2: The TXIF transmitter interrupt flag is set
CY
is automatically configured as an input,
regardless of the state of the corresponding
TRIS bit and whether or not the AUSART
receiver is enabled. The RX/DT pin data
can be read via a normal PORT read but
PORT latch data output is precluded.
when the TXEN enable bit is set.
Transmitting Data
Transmit Interrupt Flag
immediately following the Stop bit
DS41341E-page 147