PIC16C774T-I/SO View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16C774T-I/SO

28/40-Pin, 8-Bit CMOS Microcontrollers w/ 12-Bit A/D

Microchip Technology 

FIGURE 9-4: ASYNCHRONOUS TRANSMISSION

Write to TXREG

BRG output

(shift clock)

RC6/TX/CK (pin)

TXIF bit

(Transmit buffer

reg. empty flag)

Word 1

Start Bit

Bit 0

Bit 1

WORD 1

TRMT bit

(Transmit shift

reg. empty flag)

WORD 1

Transmit Shift Reg

PIC16C77X

Bit 7/8 Stop Bit

FIGURE 9-5: ASYNCHRONOUS TRANSMISSION (BACK TO BACK)

Write to TXREG

BRG output

(shift clock)

RC6/TX/CK (pin)

TXIF bit

(interrupt reg. flag)

Word 1

Word 2

Start Bit

Bit 0

Bit 1

WORD 1

Bit 7/8 Stop Bit

Start Bit

Bit 0

WORD 2

TRMT bit

(Transmit shift

reg. empty flag)

WORD 1

Transmit Shift Reg.

WORD 2

Transmit Shift Reg.

Note: This timing diagram shows two consecutive transmissions.

TABLE 9-6 REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION

Address Name

Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2

Bit 1

Bit 0

Value on:

POR,

BOR

Value on

all other

Resets

0Ch

PIR1

PSPIF(1) ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000

18h

RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x

19h

TXREG USART Transmit Register

0000 0000 0000 0000

8Ch

PIE1

PSPIE(1) ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000

98h

TXSTA CSRC TX9 TXEN SYNC —

BRGH TRMT 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 Transmission.

Note 1: Bits PSPIE and PSPIF are reserved on the 28-pin devices, always maintain these bits clear.

 1999-2013 Microchip Technology Inc.

Advance Information

DS30275B-page 103

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