PIC16F913-I/SO Microchip Technology, PIC16F913-I/SO Datasheet - Page 140

• Manufacturer Part Number: PIC16F913-I/SO
• Description: IC PIC MCU FLASH 4KX14 28SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F913-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 28-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 24
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SSP/I2C/AUSART/SPI
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 24
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT28SO-1 - SOCKET TRANSITION 28SOIC 300MIL
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC16F91X
11.3
In Synchronous Master mode, the data is transmitted in
a half-duplex manner (i.e., transmission and reception
do not occur at the same time). When transmitting data,
the reception is inhibited and vice versa. Synchronous
mode is entered by setting bit, SYNC (TXSTA<4>). In
addition, enable bit, SPEN (RCSTA<7>), is set in order
to configure the RC6/TX/CK/SCK/SCL/SEG9 and
RC7/RX/DT/SDI/SDA/SEG8 I/O pins to CK (clock) and
DT (data) lines, respectively. The Master mode indi-
cates that the processor transmits the master clock on
the CK line. The Master mode is entered by setting bit,
CSRC (TXSTA<7>).
11.3.1
The USART transmitter block diagram is shown in
Figure 11-6. The heart of the transmitter is the Transmit
(Serial) Shift Register (TSR). The shift register obtains
its data from the Read/Write Transmit Buffer register,
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available). Once the
TXREG register transfers the data to the TSR register
(occurs in one T
rupt bit, TXIF (PIR1<4>), is set. The interrupt can be
enabled/disabled by setting/clearing enable bit TXIE
(PIE1<4>). Flag bit TXIF will be set regardless of the
state of enable bit TXIE and cannot be cleared in soft-
ware. It will reset only when new data is loaded into the
TXREG register. While flag bit TXIF indicates the status
of the TXREG register, another bit, TRMT (TXSTA<1>),
shows the status of the TSR register. TRMT is a
read-only bit which is set when the TSR is empty. No
interrupt logic is tied to this bit so the user has to poll
this bit in order to determine if the TSR register is
empty. The TSR is not mapped in data memory so it is
not available to the user.
Transmission is enabled by setting enable bit, TXEN
(TXSTA<5>). The actual transmission will not occur
until the TXREG register has been loaded with data.
The first data bit will be shifted out on the next available
rising edge of the clock on the CK line. Data out is
stable around the falling edge of the synchronous clock
(Figure 11-9). The transmission can also be started by
first loading the TXREG register and then setting bit
TXEN (Figure 11-10). This is advantageous when slow
baud rates are selected, since the BRG is kept in Reset
when bits TXEN, CREN and SREN are clear. Setting
enable bit TXEN will start the BRG, creating a shift
clock immediately. Normally, when transmission is first
started, the TSR register is empty, so a transfer to the
TXREG register will result in an immediate transfer to
TSR, resulting in an empty TXREG. Back-to-back
transfers are possible.
DS41250B-page 138
USART Synchronous
Master Mode
USART SYNCHRONOUS MASTER
TRANSMISSION
CYCLE
), the TXREG is empty and inter-
Preliminary
Clearing enable bit TXEN during a transmission will
cause the transmission to be aborted and will reset the
transmitter. The DT and CK pins will revert to
high-impedance. If either bit CREN or bit SREN is set
during a transmission, the transmission is aborted and
the DT pin reverts to a high-impedance state (for a
reception). The CK pin will remain an output if bit CSRC
is set (internal clock). The transmitter logic, however, is
not reset, although it is disconnected from the pins. In
order to reset the transmitter, the user has to clear bit
TXEN. If bit SREN is set (to interrupt an on-going trans-
mission and receive a single word), then after the sin-
gle word is received, bit SREN will be cleared and the
serial port will revert back to transmitting, since bit
TXEN is still set. The DT line will immediately switch
from High-Impedance Receive mode to transmit and
start driving. To avoid this, bit TXEN should be cleared.
In order to select 9-bit transmission, the TX9
(TXSTA<6>) bit should be set and the ninth bit should
be written to bit TX9D (TXSTA<0>). The ninth bit must
be written before writing the 8-bit data to the TXREG
register. This is because a data write to the TXREG can
result in an immediate transfer of the data to the TSR
register (if the TSR is empty). If the TSR was empty and
the TXREG was written before writing the “new” TX9D,
the “present” value of bit TX9D is loaded.
Steps to follow when setting up a Synchronous Master
Transmission:
1.
2.
3.
4.
5.
6.
7.
8.
Initialize the SPBRG register for the appropriate
baud rate (Section 11.1 “USART Baud Rate
Generator (BRG)”).
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting bit TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
 2004 Microchip Technology Inc.