Asynchronous Serial Interface (Uart) Mode - NEC PD78052 User Manual

19.4.2 Asynchronous serial interface (UART) mode

In this mode, one byte of data is transmitted/received following the start bit, and full-duplex operation is possible.
A dedicated UART baud rate generator is incorporated, allowing communication over a wide range of baud rates.
In addition, the baud rate can be defined also by scaling the input clock to the ASCK pin.
The MIDI standard baud rate (31.25 kbps) can also be used by employing the dedicated UART baud rate generator.
(1) Register setting
UART mode settings are performed using serial operating mode register 2 (CSIM2), the asynchronous serial
interface mode register (ASIM), the asynchronous serial interface status register (ASIS), and the baud rate
generator control register (BRGC).
(a) Serial operating mode register 2 (CSIM2)
CSIM2 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets CSIM2 to 00H.
When the UART mode is selected, 00H should be set in CSIM2.
Symbol
<7> 6 5
CSIM2 CSIE2 0 0
Caution Ensure that bits 0 and 3 to 6 are set to 0.
454
CHAPTER 19 SERIAL INTERFACE CHANNEL 2
4 3 2 1 0
CSIM
0 0 CSCK 0
22
Address After Reset R/W
FF72H 00H R/W
CSCK Selection of Serial Operating Mode
0 UART mode
1 3-wire serial I/O mode
First Bit Specification
CSIM22
0 MSB
1 LSB
CSIE2 Operation Control in 3-wire Serial I/O Mode
0 Operation stopped
1 Operation enabled