upd78f0114hgb-8es-a Renesas Electronics Corporation., upd78f0114hgb-8es-a Datasheet - Page 494

• Manufacturer Part Number: upd78f0114hgb-8es-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

494
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
TXSF6 during
continuous
transmission:
Bit 0 of ASIF6
Normal
reception
Serial clock
generation
Details of
Function
The read value of the SBTT6 bit is always 0. SBTT6 is automatically cleared to 0
at the end of SBF transmission.
Before rewriting the DIR6 and TXDLV6 bits, clear the TXE6 and RXE6 bits to 0.
When using the 78K0/KC1+ to evaluate the program of a mask ROM version of
the 78K0/KC1, set the SBTT6, SBL62, SBL61, and SBL60 bits to 0, 1, 0, 1,
respectively.
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 UART6 is used in the LIN communication
operation.
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 UART6 is used in the LIN communication operation, 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.
Keep the baud rate error during transmission to within the permissible error range
at the reception destination.
APPENDIX D LIST OF CAUTIONS
User’s Manual U16961EJ4V0UD
Cautions
p. 278
p. 278
p. 278
p. 280
p. 281
p. 285
p. 287
p. 287
p. 287
p. 287
p. 287
p. 291
p. 291
p. 291
p. 297
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