NEC uPD78052(A) User Manual
445
CHAPTER 19 SERIAL INTERFACE CHANNEL 2
Note
When SCK is set to 1 and the baud rate generator output is selected, the ASCK pin can be used as
an input/output port.
Cautions 1. When the 3-wire serial I/O mode is selected, 00H should be set in ASIM.
2. The serial transmit/receive operation must be stopped before changing the operating
mode.
(2) Asynchronous serial interface mode register (ASIM)
This register is set when serial interface channel 2 is used in the asynchronous serial interface mode.
ASIM is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ASIM to 00H.
Figure 19-4. Asynchronous Serial Interface Mode Register Format
<6>
5
4
3
2
1
0
<7>
Symbol
ASIM
TXE
RXE
PS1
PS0
CL
SL
ISRM
SCK
FF70H 00H R/W
Address After Reset R/W
SCK
0
1
Clock Selection in Asynchronous Serial Interface
Mode
Mode
Input clock from off-chip to ASCK pin
Dedicated baud rate generator output
Note
ISRM
0
1
Control of Reception Completion Interrupt Request
in Case of Error Generation
in Case of Error Generation
Reception completion interrupt request generated
in case of error generation
in case of error generation
Reception completion interrupt request not
generated in case of error generation
generated in case of error generation
SL
Transmit Data Stop Bit Length Specification
CL
1
Character Length Specification
7 bits
8 bits
RXE
0
1
Receive Operation Control
Receive operation stopped
Receive operation enabled
TXE
0
1
Transmit Operation Control
Transmit operation stopped
Transmit operation enabled
PS1
0
1
0
1 bit
1
2 bits
0
Parity Bit Specification
No Parity
Even parity
PS0
0
1
0 parity always added in transmission
No parity test in reception (parity error not
generated)
No parity test in reception (parity error not
generated)
0
1
1
Odd parity
0