upd78f0114m6gb-8es Renesas Electronics Corporation., upd78f0114m6gb-8es Datasheet - Page 523

• Manufacturer Part Number: upd78f0114m6gb-8es
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

Serial
interface
UART6
Function
ASICL6:
Asynchronous
serial interface
control register
6
POWER6,
TXE6, RXE6:
Bits 7, 6, and 5
of ASIM6
UART mode
Parity type and
operation
Continuous
transmission
TXBF6 during
continuous
transmission:
Bit 1 of ASIF6
During
continuous
transmission:
Bit 1 of ASIF6
Normal
reception
Details of
Function
ASICL6 can be refreshed (the same value is written) by software during a
communication operation (when bit 7 (POWER6) and bit 6 (TXE6) of ASIM6 = 1
or bit 7 (POWER6) and bit 5 (RXE6) of ASIM6 = 1). Note, however, that
communication is started by the refresh operation because bit 6 (SBRT6) of
ASICL6 is cleared to 0 when communication is completed (when an interrupt
signal is generated).
In the case of an SBF reception error, return the mode to the SBF reception
mode.
The status of the SBRF6 flag is held (1).
Before setting the SBRT6 bit, make sure that bit 7 (POWER6) and bit 5 (RXE6)
of ASIM6 = 1.
The read value of the SBRT6 bit is always 0. SBRT6 is automatically cleared to
0 after SBF reception has been correctly completed.
Before rewriting the DIR6 and TXDLV6 bits, clear the TXE6 and RXE6 bits to 0.
Clear POWER6 to 0 after clearing TXE6 and RXE6 to 0 to set the operation stop
mode.
To start the operation, set POWER6 to 1, and then set TXE6 and RXE6 to 1.
Take relationship with the other party of communication when setting the port
mode register and port register.
Fix the PS61 and PS60 bits to 0 when the device is incorporated in LIN.
The TXBF6 and TXSF6 flags of the ASIF6 register change from “10” to “11”, and
to “01” during continuous transmission. To check the status, therefore, do not
use a combination of the TXBF6 and TXSF6 flags for judgment. Read only the
TXBF6 flag when executing continuous transmission.
When the device is incorporated in a LIN, the continuous transmission function
cannot be used. Make sure that asynchronous serial interface transmission
status register 6 (ASIF6) is 00H before writing transmit data to transmit buffer
register 6 (TXB6).
To transmit data continuously, write the first transmit data (first byte) to the TXB6
register. Be sure to check that the TXBF6 flag is “0”. If so, write the next
transmit data (second byte) to the TXB6 register. If data is written to the TXB6
register while the TXBF6 flag is “1”, the transmit data cannot be guaranteed.
To initialize the transmission unit upon completion of continuous transmission, be
sure to check that the TXSF6 flag is “0” after generation of the transmission
completion interrupt, and then execute initialization. If initialization is executed
while the TXSF6 flag is “1”, the transmit data cannot be guaranteed.
During continuous transmission, an overrun error may occur, which means that
the next transmission was completed before execution of INTST6 interrupt
servicing after transmission of one data frame. An overrun error can be detected
by developing a program that can count the number of transmit data and by
referencing the TXSF6 flag.
Be sure to read receive buffer register 6 (RXB6) even if a reception error occurs.
Otherwise, an overrun error will occur when the next data is received, and the
reception error status will persist.
Reception is always performed with the “number of stop bits = 1”. The second
stop bit is ignored.
Be sure to read asynchronous serial interface reception error status register 6
(ASIS6) before reading RXB6.
APPENDIX D LIST OF CAUTIONS
User’s Manual U16227EJ3V0UD
Cautions
p. 279
p. 279
p. 279
p. 279
p. 279
p. 281
p. 282
p. 286
p. 288
p. 288
p. 288
p. 288
p. 288
p. 292
p. 292
p. 292
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