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CHAPTER 14 SERIAL INTERFACE UART
(5) Receive control circuit
The receive control circuit 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.
14.3 UART Control Registers
The UART uses the following three types of registers for control functions.
• 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 the value to 00H.
Figure 14-2 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 (R
X
D) to the input mode (PM53 = 1)
• When transmitting
Set P54 (T
X
D) to the output mode (PM54 = 0)
• When transceiving
Set P53 to the input mode and P54 to the output mode
Summary of Contents for mPD780973 Series
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