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Clock asynchronous serial I/O (UART) mode
Under
development
Preliminary Specifications REV.B3
Specifications in this manual are tentative and subject to change.
Mitsubishi Microcomputers
M32C/83 group
SINGLE-CHIP 16/32-BIT CMOS MICROCOMPUTER
182
Item
Specification
Transfer data format
Character bit (transfer data): 7 bits, 8 bits, or 9 bits as selected
Start bit: 1 bit
Parity bit: Odd, even, or nothing as selected
Stop bit: 1 bit or 2 bits as selected
Transfer clock
When internal clock is selected (bit 3 at addresses 036816, 02E816, 033816, 032816,
02F816 = “0”) : fi/16(m+1) (Note 1) fi = f1, f8, f2n
When external clock is selected (bit 3 at addresses 036816, 02E816, 033816, 032816,
02F816 =“1”) : fEXT/16(m+1)(Note 1, 2)
Transmission/reception control
_______
_______ _______
CTS function, RTS function, CTS/RTS function chosen to be invalid
Transmission start condition
To start transmission, the following requirements must be met:
- Transmit enable bit (bit 0 at addresses 036D16, 02ED16, 033D16, 032D16, 02FD16) = “1”
- Transmit buffer empty flag (bit 1 at addresses 036D16, 02ED16, 033D16, 032D16,
02FD16) = “0”
_______
- When CTS function selected, CTS input level = “L”
- TxD output is selected by the corresponding peripheral function select register A, B
and C.
Reception start condition
To start reception, the following requirements must be met:
- Receive enable bit (bit 2 at addresses 036D16, 02ED16, 033D16, 032D16, 02FD16) = “1”
- Start bit detection
Interrupt request
When transmitting
generation timing
- Transmit interrupt cause select bits (bit 4 at address 036D16, 02ED16, 033D16,
032D16, 02FD16) = “0”: Interrupts requested when data transfer from UARTi transfer
buffer register to UARTi transmit register is completed
- Transmit interrupt cause select bits (bit 4 at address 036D16, 02ED16, 033D16,
032D16, 02FD16) = “1”: Interrupts requested when data transmission from UARTi
transfer register is completed
When receiving
- Interrupts requested when data transfer from UARTi receive register to UARTi
receive buffer register is completed
Error detection
Overrun error (Note 3)
This error occurs when the next data is started to receive and 6.5 transfer
clock is elapsed before UARTi receive buffer register are read out.
(2) Clock asynchronous serial I/O (UART) mode
The UART mode allows transmitting and receiving data after setting the desired transfer rate and transfer
data format. Tables 1.19.1 and 1.19.2 list the specifications of the UART mode. Figure 1.19.1 shows the
UARTi transmit/receive mode register.
Table 1.19.1. Specifications of UART Mode (1/2)
Note 1: ‘m’ denotes the value 0016 to FF16 that is set to the UARTi bit rate generator.
Note 2: fEXT is input from the CLKi pin.
Note 3: If an overrun error occurs, the UARTi receive buffer will be over written with the next data.