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CHAPTER 20 SERIAL INTERFACE CHANNEL 2
20.4.2 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 by scaling the input clock to the ASCK pin.
The MIDI standard baud rate (31.25 kbps) can be used by employing the dedicated UART baud rate generator.
(1) Register setting
UART mode is set 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.
6543210<7>
Symbol
CSIM2 CSIE2 0 0 0 0
CSIM
22
CSCK 0
CSCK
0
1
Clock Selection in 3-wire Serial I/O Mode
Input clock from off-chip to SCK2 pin
Dedicated baud rate generator output
CSIM22
0
1
First Bit Specification
MSB
LSB
CSIE2
0
1
Operation Control in 3-wire Serial I/O Mode
Operation stopped
Operation enabled
FF72H 00H R/W
Address After Reset R/W
Caution Ensure that bit 0 and bits 3 through 6 are set to 0.