PIC18F2220 MICROCHIP [Microchip Technology], PIC18F2220 Datasheet - Page 207

• Manufacturer Part Number: PIC18F2220
• Description: 28/40/44-Pin High-Performance, Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology
• Manufacturer: MICROCHIP [Microchip Technology]

To set up an Asynchronous Transmission:
1.
2.
3.
4.
FIGURE 18-5:
TABLE 18-7:
 2003 Microchip Technology Inc.
INTCON
PIR1
PIE1
IPR1
RCSTA
RCREG
TXSTA
SPBRG
Legend: x = unknown, - = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous reception.
Note 1:
Name
Initialize the SPBRG register for the appropriate
baud rate. If a high-speed baud rate is desired,
set bit BRGH (Section 18.2 “USART Baud
Rate Generator (BRG)”).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set Transmit bit,
TX9. Can be used as address/data bit.
RX (pin)
Rcv Shift
Reg
Rcv Buffer Reg
Read Rcv
Buffer Reg
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
The PSPIF, PSPIE and PSPIP bits are reserved on the PIC18F2X20 devices; always maintain these bits clear.
This timing diagram shows three words appearing on the RX input. The RCREG (Receive Buffer) is read after the third word,
causing the OERR (Overrun) bit to be set.
USART Receive Register
Baud Rate Generator Register
GIE/GIEH
PSPIE
PSPIP
PSPIF
CSRC
SPEN
Bit 7
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
(1)
(1)
(1)
Start
ASYNCHRONOUS RECEPTION
bit
PEIE/
GIEL
ADIF
ADIE
ADIP
Bit 6
RX9
TX9
bit 0
TMR0IE INT0IE
bit 1
SREN
TXEN
RCIE
RCIP
RCIF
Bit 5
CREN ADDEN FERR
SYNC
TXIE
TXIP
Bit 4
TXIF
bit 7/8
PIC18F2220/2320/4220/4320
Stop
bit
SSPIE CCP1IE TMR2IE TMR1IE 0000 0000
SSPIP CCP1IP TMR2IP TMR1IP 1111 1111
SSPIF CCP1IF TMR2IF TMR1IF 0000 0000
RBIE
Bit 3
—
Word 1
RCREG
Start
bit
TMR0IF INT0IF
BRGH
Bit 2
bit 0
5.
6.
7.
8.
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 the GIE and PEIE
bits in the INTCON register (INTCON<7:6>) are
set.
OERR
TRMT
Bit 1
bit 7/8
Word 2
RCREG
Stop
RX9D
TX9D
RBIF
Bit 0
bit
Start
bit
0000 000x
0000 -00x
0000 0000
0000 -010
0000 0000
POR, BOR
Value on
bit 7/8
DS39599C-page 205
0000 000u
0000 0000
0000 0000
1111 1111
0000 -00x
0000 0000
0000 -010
0000 0000
Stop
bit
Value on
all other
Resets