PIC16F871-I/PT Microchip Technology Inc., PIC16F871-I/PT Datasheet - Page 69

• Manufacturer Part Number: PIC16F871-I/PT
• Description: 44 PIN, 7 KB FLASH, 128 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F871-I/PT

• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 33
• Interface: USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TQFP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

When setting up an Asynchronous Transmission,
follow these steps:
1.
2.
3.
4.
FIGURE 9-2:
FIGURE 9-3:
TABLE 9-5:
 2003 Microchip Technology Inc.
0Bh, 8Bh,
10Bh,18Bh
0Ch
18h
19h
8Ch
98h
99h
Legend:
Note 1:
Address
Write to TXREG
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
TXIF bit
(Interrupt Reg. Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Note:
Write to TXREG
BRG Output
(Shift Clock)
RC6/TX/CK (pin)
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Initialize the SPBRG register for the appropriate
baud rate. If a high speed baud rate is desired,
set bit BRGH (Section 9.1).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, then set enable bit
TXIE.
If 9-bit transmission is desired, then set transmit
bit TX9.
x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for asynchronous transmission.
Bits PSPIE and PSPIF are reserved on the PIC16F870; always maintain these bits clear.
This timing diagram shows two consecutive transmissions.
INTCON
PIR1
RCSTA
TXREG USART Transmit Register
PIE1
TXSTA
SPBRG Baud Rate Generator Register
Name
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
PSPIF
PSPIE
ASYNCHRONOUS MASTER TRANSMISSION
ASYNCHRONOUS MASTER TRANSMISSION (BACK TO BACK)
CSRC
SPEN
Bit 7
GIE
Word 1
Transmit Shift Reg.
Word 1
Transmit Shift Reg
Word 1
Word 1
(1)
(1)
ADIE
PEIE
ADIF
Bit 6
RX9
TX9
START Bit
START Bit
Word 2
SREN
TXEN
RCIF
RCIE
Bit 5
T0IE
Bit 0
CREN
SYNC
INTE
TXIE
Bit 4
TXIF
Bit 0
RBIE
Bit 3
—
—
—
—
Bit 1
Word 1
Bit 1
5.
6.
7.
8.
Word 1
CCP1IF
CCP1IE TMR2IE
BRGH
FERR
Bit 2
T0IF
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to the TXREG register (starts
transmission).
If using interrupts, ensure that GIE and PEIE
(bits 7 and 6) of the INTCON register are set.
TMR2IF
OERR
TRMT
Bit 1
INTF
PIC16F870/871
Bit 7/8
Word 2
Transmit Shift Reg.
Bit 7/8
TMR1IE
TMR1IF
RX9D
TX9D
R0IF
Bit 0
STOP Bit START Bit
STOP Bit
0000 000x
0000 -000
0000 -00x
0000 0000
0000 -000
0000 -010
0000 0000
POR, BOR
Value on:
DS30569B-page 67
Word 2
0000 000u
0000 -000
0000 -00x
0000 0000
0000 -000
0000 -010
0000 0000
Value on
RESETS
all other
Bit 0