NEC 78K0S/KA1+ User Manual page 396

Function Details of
Function
Serial TXB6: Transmit
interface buffer register 6
UART6
ASIM6:
Registers
controlling
serial interface
UART6
ASIS6:
Asynchronous
serial interface
reception error
status register 6
ASIF6:
Asynchronous
serial interface
transmission
status register 6 To initialize the transmission unit upon completion of continuous transmission, be
CKSR6: Clock
selection
register 6
BRGC6: Baud
rate generator
control register
6
ASICL6:
Asynchronous
serial interface
control register
6
396
APPENDIX D LIST OF CAUTIONS
Do not refresh (write the same value to) TXB6 by software during a
communication operation (when bit 7 (POWER6) and bit 6 (TXE6) of
asynchronous serial interface operation mode register 6 (ASIM6) are 1 or when
bit 7 (POWER6) and bit 5 (RXE6) of ASIM6 are 1).
At startup, set POWER6 to 1 and then set TXE6 to 1. To stop the operation,
clear TXE6 to 0, and then clear POWER6 to 0.
At startup, set POWER6 to 1 and then set RXE6 to 1. To stop the operation,
clear RXE6 to 0, and then clear POWER6 to 0.
Set POWER6 to 1 and then set RXE6 to 1 while a high level is input to the RxD6
pin. If POWER6 is set to 1 and RXE6 is set to 1 while a low level is input,
reception is started.
Clear the TXE6 and RXE6 bits to 0 before rewriting the PS61, PS60, and CL6 bits.
Fix the PS61 and PS60 bits to 0 when mounting the device on LIN.
Make sure that TXE6 = 0 when rewriting the SL6 bit. Reception is always
performed with "the number of stop bits = 1", and therefore, is not affected by the
set value of the SL6 bit.
Make sure that RXE6 = 0 when rewriting the ISRM6 bit.
The operation of the PE6 bit differs depending on the set values of the PS61 and
PS60 bits of asynchronous serial interface operation mode register 6 (ASIM6).
The first bit of the receive data is checked as the stop bit, regardless of the
number of stop bits.
If an overrun error occurs, the next receive data is not written to receive buffer
register 6 (RXB6) but discarded.
Be sure to read ASIS6 before reading receive buffer register 6 (RXB6).
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.
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.
Make sure POWER6 = 0 when rewriting TPS63 to TPS60.
Make sure that bit 6 (TXE6) and bit 5 (RXE6) of the ASIM6 register = 0 when
rewriting the MDL67 to MDL60 bits.
The baud rate is the output clock of the 8-bit counter divided by 2.
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). However, if the SBRT6 = 1
and SBTT = 1 are set in the refresh operation during the SBF reception (SBRF6
= 1) or SBF transmission (between the SBTT6 setting (1) and the INTST6
occurrence), it triggers the SBF reception and SBF transmission again, so do not
set.
In the case of an SBF reception error, return the mode to the SBF reception
mode again and hold (1) the status of the SBRF6 flag.
User's Manual U16898EJ3V0UD
Cautions
(10/17)
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