TMP89FS60 datasheet(238/410 Pages) TOSHIBA

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16. Asynchronous Serial Interface (UART)

16.11 Transmit/Receive Operation

TMP89FS60

RA001

16.11Transmit/Receive Operation

16.11.1Data transmit operation

Set UART0CR1<TXE> to "1". Check UART0SR<TBFL> = "0", and then write data into TD0BUF (transmit

data buffer). Writing data into TD0BUF sets UART0SR<TBFL> to "1", transfers the data to the transmit shift

whose number is specified in UART0CR1<STBT> and a parity bit if parity addition is specified. Select the

data transfer baud rate using UART0CR1<BRG>, UART0CR2<RTSEL> and UART0DR. When data trans-

mission starts, the transmit buffer full flag UART0SR<TBFL> is cleared to "0" and an INTTXD0 interrupt

request is generated.

Note 1: After data is written into TD0BUF, if new data is written into TD0BUF before the previous data is transferred

to the shift register, the new data is written over the previous data and is transferred to the shift register.

Note 2: Under the conditions shown in Table 16-9, the TXD0 pin output is fixed at the L or H level according to the

setting of UART0CR1<IRDASEL>.

16.11.2Data receive operation

Set UART0CR1<RXE> to "1". When data is received via the RXD0 pin, the received data is transferred to

RD0BUF (receive data buffer). At this time, the transmitted data includes a start bit, stop bit(s) and a parity bit

if parity addition is specified. When the stop bit(s) are received, data only is extracted and transferred to

RD0BUF (receive data buffer). Then the receive buffer full flag UART0SR<RBFL> is set and an INTRXD0

interrupt request is generated. Set the data transfer baud rate using UART0CR1<BRG>, UART0CR2<RTSEL>

and UART0DR.

If an overrun error occurs when data is received, the data is not transferred to RD0BUF (receive data buffer)

but discarded; data in the RD0BUF is not affected.

Table 16-9 TXD0 Pin Output

Condition

TXD0 pin output

IRDASEL="0"

IRDASEL="1"

When UART0CR1<TXE> is "0"

H level

L level

From when "1" is written to

UART0CR1<TXE> to when the trans-

mitted data is written to TD0BUF

When the STOP, IDLE0 or SLEEP0

mode is active

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