PIC16F628A-E/SO Microchip Technology, PIC16F628A-E/SO Datasheet - Page 82

• Manufacturer Part Number: PIC16F628A-E/SO
• Description: IC MCU FLASH 2KX14 EEPROM 18SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F628A-E/SO

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 18-SOIC (7.5mm Width)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Ram Size: 224 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 224 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• 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, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3DBF648 - BOARD DAUGHTER ICEPIC3AC162053 - HEADER INTERFACE ICD,ICD2 18DIP
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC16F627A/628A/648A
12.2.2
The receiver block diagram is shown in Figure 12-4.
The data is received on the RB1/RX/DT pin and drives
the data recovery block. The data recovery block is
actually a high-speed shifter operating at x16 times the
baud rate, whereas the main receive serial shifter
operates at the bit rate or at F
When Asynchronous mode is selected, reception is
enabled by setting bit CREN (RCSTA<4>).
The heart of the receiver is the Receive (serial) Shift
Register (RSR). After sampling the Stop bit, the
received data in the RSR is transferred to the RCREG
register (if it is empty). If the transfer is complete, flag
bit RCIF (PIR1<5>) is set. The actual interrupt can be
enabled/disabled by setting/clearing enable bit RCIE
(PIE1<5>). Flag bit RCIF is a read-only bit, which is
cleared by the hardware. It is cleared when the RCREG
register has been read and is empty. The RCREG is a
FIGURE 12-4:
DS40044G-page 82
RB1/RX/DT
USART ASYNCHRONOUS
RECEIVER
Baud Rate Generator
x64 Baud Rate CLK
USART RECEIVE BLOCK DIAGRAM
SPBRG
Pin Buffer
and Control
RSR<8>
SPEN
ADEN
ADEN
RX9
RX9
OSC
.
Data
Recovery
Interrupt
CREN
÷ 64
÷ 16
or
Enable
Load of
Receive
Buffer
double buffered register (i.e., it is a two-deep FIFO). It
is possible for two bytes of data to be received and
transferred to the RCREG FIFO and a third byte begin
shifting to the RSR register. On the detection of the
Stop bit of the third byte, if the RCREG register is still
full, then overrun error bit OERR (RCSTA<1>) will be
set. The word in the RSR will be lost. The RCREG
register can be read twice to retrieve the two bytes in
the FIFO. Overrun bit OERR has to be cleared in soft-
ware. This is done by resetting the receive logic (CREN
is cleared and then set). If bit OERR is set, transfers
from the RSR register to the RCREG register are inhib-
ited, so it is essential to clear error bit OERR if it is set.
Framing error bit FERR (RCSTA<2>) is set if a Stop bit
is detected as clear. Bit FERR and the 9th receive bit
are buffered the same way as the receive data. Read-
ing the RCREG, will load bits RX9D and FERR with
new values, therefore it is essential for the user to read
the RCSTA register before reading RCREG register in
order not to lose the old FERR and RX9D information.
RCIF
RCIE
RX9
MSb
Stop
RX9D
RX9D
(8)
OERR
7
RCREG register
RCREG register
RSR register
• • •
© 2009 Microchip Technology Inc.
8
Data Bus
8
8
1
FERR
0
Start
LSb
FIFO