PIC16C765-I/P Microchip Technology, PIC16C765-I/P Datasheet - Page 83

• Manufacturer Part Number: PIC16C765-I/P
• Description: IC MCU OTP 8KX14 USB 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C765-I/P

• Core Size: 8-Bit
• Program Memory Size: 14KB (8K x 14)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 24MHz
• Connectivity: SCI, UART/USART, USB
• Number Of I /o: 33
• Program Memory Type: OTP
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.35 V ~ 5.25 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16C
• No. Of I/o's: 33
• Ram Memory Size: 256Byte
• Cpu Speed: 24MHz
• No. Of Timers: 3
• Processor Series: PIC16C
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Maximum Clock Frequency: 24 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3
• Operating Supply Voltage: 4.35 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ISPICR1 - ADAPTER IN-CIRCUIT PROGRAMMING444-1001 - DEMO BOARD FOR PICMICRO MCU
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: Q975613

11.2.2
The receiver block diagram is shown in Figure 11-4.
The data is received on the RC7/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 oper-
ates at the bit rate or at F
Once Asynchronous mode is selected, reception is
enabled by setting bit CREN (RCSTA<4>).
The heart of the receiver is the receive (serial) shift reg-
ister (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
(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
double buffered register, i.e., it is a two deep FIFO. It is
FIGURE 11-4: USART RECEIVE BLOCK DIAGRAM
FIGURE 11-5: ASYNCHRONOUS RECEPTION
2000 Microchip Technology Inc.
RX (pin)
Rcv shift
reg
Rcv buffer reg
Read Rcv
buffer reg
RCREG
RCIF
(interrupt flag)
OERR bit
CREN
Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
USART ASYNCHRONOUS RECEIVER
by
RC7/RX/DT
causing the OERR (overrun) bit to be set.
setting/clearing
Baud Rate Generator
Start
bit
INT
SPBRG
Pin Buffer
and Control
bit0
.
SPEN
bit1
enable
bit
bit7/8
Data
Recovery
Interrupt
RCIE
Preliminary
Stop
bit
CREN
WORD 1
RCREG
Start
bit
bit0
possible for two bytes of data to be received and trans-
ferred to the RCREG FIFO and a third byte to 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 reg-
ister can be read twice to retrieve the two bytes in the
FIFO. Overrun bit OERR has to be cleared in software.
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 inhibited,
so it is essential to clear error bit OERR if it is set. Fram-
ing 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. Reading
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
(8)
bit7/8
WORD 2
RCREG
OERR
PIC16C745/765
7
RSR Register
Stop
bit
RCREG Register
8
Start
Data Bus
bit
1
FERR
0
LSb
Start
bit7/8
FIFO
DS41124C-page 83
Stop
bit