Serial Interface Control Registers - NEC mPD780852 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 (ASIM). During a receive operation, it performs error checking, such as for parity errors, and sets
various values to the asynchronous serial interface status register (ASIS) according to the type of error that is
detected.

13.3 Serial Interface Control Registers

The following three types of registers are used to control the serial interface UART.
• Asynchronous serial interface mode register (ASIM)
• Asynchronous serial interface status register (ASIS)
• Baud rate generator control register (BRGC)
(1) Asynchronous serial interface mode register (ASIM)
This is an 8-bit register that controls UART's serial transfer operations.
ASIM is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears ASIM to 00H.
Figure 13-2 shows the format of ASIM.
Caution In UART mode, set the port mode register (PM5X) as follows. Besides that, set all output
latches to 0.
• When receiving
Set P53 (RxD) to the input mode (PM53 = 1)
• When transmitting
Set P54 (TxD) to the output mode (PM54 = 0)
• When transceiving
Set P53 to the input mode and P54 to the output mode
CHAPTER 13 SERIAL INTERFACE UART
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