UPD78F0138 NEC, UPD78F0138 Datasheet - Page 282

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

13.4.2 Asynchronous serial interface (UART) mode
baud rates.
(1) Registers used
282
POWER0
In this mode, 1-byte data is transmitted/received following a start bit, and a full-duplex operation can be performed.
A dedicated UART baud rate generator is incorporated, so that communication can be executed at a wide range of
Note Can be set as port function.
Remark ×:
0
1
• Asynchronous serial interface operation mode register 0 (ASIM0)
• Asynchronous serial interface reception error status register 0 (ASIS0)
• Baud rate generator control register 0 (BRGC0)
• Port mode register 1 (PM1)
• Port register 1 (P1)
<1> Set the BRGC0 register (see Figure 13-4).
<2> Set bits 1 to 4 (SL0, CL0, PS00, and PS01) of the ASIM0 register (see Figure 13-2).
<3> Set bit 7 (POWER0) of the ASIM0 register to 1.
<4> Set bit 6 (TXE0) of the ASIM0 register to 1. → Transmission is enabled.
<5> Write data to the TXS0 register. → Data transmission is started.
The basic procedure of setting an operation in the UART mode is as follows.
Caution Take relationship with the other party of communication when setting the port mode register
The relationship between the register settings and pins is shown below.
Set bit 5 (RXE0) of the ASIM0 register to 1. → Reception is enabled.
TXE0
POWER0: Bit 7 of asynchronous serial interface operation mode register 0 (ASIM0)
TXE0:
RXE0:
PM1×:
P1×:
0
0
1
1
and port register.
RXE0
0
1
0
1
don’t care
Bit 6 of ASIM0
Bit 5 of ASIM0
Port mode register
Port output latch
Table 13-2. Relationship Between Register Settings and Pins
PM10
×
×
0
0
Note
Note
CHAPTER 13 SERIAL INTERFACE UART0
P10
×
×
Note
Note
1
1
User’s Manual U16228EJ2V0UD
PM11
×
×
1
1
Note
Note
P11
×
×
Note
×
Note
×
Transmission/
Transmission
Operation
Reception
reception
UART0
Stop
TxD0/SCK10/P10
SCK10/P10
SCK10/P10
TxD0
TxD0
Pin Function
RxD0/SI10/P11
SI10/P11
SI10/P11
RxD0
RxD0