216
CHAPTER 13 SERIAL INTERFACE (UART0)
Preliminary User’s Manual U16035EJ1V0UM
(5) Receive controller
The receive controller controls receive operations based on the values set to the asynchronous serial interface
mode register 0 (ASIM0). During a receive operation, it performs error checking, such as for parity errors, and
sets various values to the asynchronous serial interface status register 0 (ASIS0) according to the type of error
that is detected.
13.3 Registers to Control Serial Interface
The serial interface (UART0) uses the following three types of registers for control functions.
• Asynchronous serial interface mode register 0 (ASIM0)
• Asynchronous serial interface status register 0 (ASIS0)
• Baud rate generator control register 0 (BRGC0)
(1) Asynchronous serial interface mode register 0 (ASIM0)
This is an 8-bit register that controls serial interface (UART0)’s serial transfer operations.
ASIM0 is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ASIM0 to 00H.
Figure 13-3 shows the format of ASIM0.
Caution
In UART mode, set the port mode register (PMXX) as follows. Set the output latch of the port
set to output mode (PMXX = 0) to 0.
• During receive operation
Set P23 (RXD0) to input mode (PM23 = 1)
• During transmit operation
Set P24 (TXD0) to output mode (PM24 = 0)
• During transmit/receive operation
Set P23 to input mode, and P24 to output mode
