Datasheet

Table Of Contents
2002 Microchip Technology Inc. Preliminary DS40044A-page 81
PIC16F627A/628A/648A
Follow these steps when setting up an Asynchronous
Reception:
1. TRISB<1> bit needs to be set and TRISB<2> bit
cleared in order to configure pins RB2/TX/CK
and RB1/RX/DT as the Universal Synchronous
Asynchronous Receiver Transmitter pins.
2. Initialize the SPBRG register for the appropriate
baud rate. If a high-speed baud rate is desired,
set bit BRGH. (Section 12.1).
3. Enable the asynchronous serial port by clearing
bit SYNC, and setting bit SPEN.
4. If interrupts are desired, then set enable bit
RCIE.
5. If 9-bit reception is desired, then set bit RX9.
6. Enable the reception by setting bit CREN.
7. Flag bit RCIF will be set when reception is com-
plete and an interrupt will be generated if enable
bit RCIE was set.
8. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If any error occurred, clear the error by clearing
enable bit CREN.
TABLE 12-7: REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
POR
Value on
all other
RESETS
0Ch PIR1
EEIF CMIF RCIF TXIF CCP1IF TMR2IF TMR1IF 0000 -000 0000 -000
18h RCSTA SPEN RX9
SREN CREN ADEN FERR OERR RX9D 0000 000x 0000 000x
1Ah RCREG
USART Receive data registe
r
0000 0000 0000 0000
8Ch PIE1
EEIE CMIE RCIE TXIE CCP1IE TMR2IE TMR1IE 0000 -000 0000 -000
98h TXSTA
CSRC TX9 TXEN SYNC —BRGHTRMT TX9D 0000 -010 0000 -010
99h SPBRG Baud Rate Generator Register 0000 0000 0000 0000
Legend: x = unknown, - = unimplemented locations read as '0'. Shaded cells are not used for Asynchronous Reception.