Registers To Control Serial Interface - NEC mPD780024AS Series Preliminary User's Manual

(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
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CHAPTER 13 SERIAL INTERFACE (UART0)
Preliminary User's Manual U16035EJ1V0UM