UPD78F9234MC-5A4-A Datasheet, PDF (404/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

APPENDIX D LIST OF CAUTIONS
Function
Details of
Function
Cautions
(13/20)
Page
Serial
interface
UART6
Multiplier
UART mode
Take the relationship with the other party of communication into consideration p.199
when setting the port mode register and port register. In order to avoid the
generation of unintended start bits (falling signals), set PM43 to 0 (output) after
having set P43 to 1.
Parity types and Fix the PS61 and PS60 bits to 0 when the interface is used in LIN
operation
communication operation.
p.203
Continuous
transmission
Use the value of the TXBF6 flag to judge whether continuous transmission is
possible. Do not write the next transmit data, by making a judgment only by
the fact that the TXSF6 flag has been set to 1.
p.205
When the interface is used in 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).
p.205
TXBF6 during
continuous
transmission: Bit
1 of ASIF6
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.
p.205
TXSF6 during
continuous
transmission: Bit
0 of ASIF6
To initialize the transmission unit upon completion of continuous transmission, p.205
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.
Normal reception
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.
p.209
Reception is always performed with the “number of stop bits = 1”. The second p.209
stop bit is ignored.
Be sure to read asynchronous serial interface reception error status register 6 p.209
(ASIS6) before reading RXB6.
Generation of
serial clock
Keep the baud rate error during transmission to within the permissible error
range at the reception destination.
p.215
Make sure that the baud rate error during reception satisfies the range shown p.215
in (4) Permissible baud rate range during reception.
Permissible baud
rate range during
reception
Make sure that the baud rate error during reception is within the permissible
error range, by using the calculation expression shown below.
p.217
MUL0: 16-bit
multiplication
result storage
register 0
Although this register is manipulated with a 16-bit memory manipulation
instruction, it can be also manipulated with an 8-bit memory manipulation
instruction. When using an 8-bit memory manipulation instruction, however,
access the register by means of direct addressing.
p.220
MULC0: control
register 0
Be sure to clear bits 1 to 7 to 0.
p.222
402
User’s Manual U17446EJ5V0UD