M30222 Datasheet, PDF (113/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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MITSUBISHI MICROCOMPUTERS
M30222 Group
Rev. G
Clock Synchronous Serial I/O Mode
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
(1) Clock synchronous serial I/O mode
The clock synchronous serial I/O mode uses a transfer clock to transmit and receive data. Tables 1.34 and
1.35 list the specifications of the clock synchronous serial I/O mode. Figure 1.87 shows the UARTi
transmit/receive mode register.
Table 1.34. Specifications of clock synchrounous serial I/O mode (1)
Item
Transfer data format
Transfer clock
Transmission/
reception control
Transmission start
condition
Receiving start
condition
Interrupt request
generation timing
Error detection
Specification
Transfer data length: 8 bits
When internal clock is selected (bit 3 at addresses 03A0₁₆, 03A8₁₆, 0378₁₆ = 0 ): fi/
2 (n+1) (Note 1) fi = f1, f8, f32
When external clock is selected (bit 3 at addresses 03A0₁₆, 03A8₁₆ 0378₁₆ = 1 ):
Input from CLKi pin
CTS function/RTS function/CTS, RTS function chosen to be invalid
To start transmission, the following requirements must be met:
-Transmit enable bit (bit 0 at addresses 03A5₁₆, 03AD₁₆, 037D₁₆) = 1
-Transmit buffer empty flag (bit 1 at addresses 03A5₁₆, 03AD₁₆, 037D₁₆) = 0
-When CTS function selected, CTS input level = L
If external clock is selected, the following requirements must also me be:
-CLKi polarity select bit (bit 6 at addresses 03A4₁₆, 03AC₁₆, 037C₁₆,) = 0 : CLKi
input level = H
-CLKi polarity select bit (bit 6 at addresses 03A4₁₆, 03AC₁₆, 037C₁₆) = 1 : CLKi
input level = L
To start reception, the following requirement must be met:
-Receive enable bit (bit 2 at addresses 03A5₁₆, 03AD₁₆, 037D₁₆) = 1
-Transmit enable bit (bit 0 at addresses 03A5₁₆, 03AD₁₆, 037D₁₆) = 1
-Transmit buffer empty flag (bit 1 at addresses 03A5₁₆, 03AD₁₆, 037D₁₆) = 0
If external clock is selected, the following requirements must also be met:
-CLKi polarity select bit (bit 6 at addresses 03A4₁₆, 03AC₁₆, 037C₁₆) = 0 : CLKi
input level = H
-CLKi polarity select bit (bit 6 at addresses 03A4₁₆, 03AC₁₆, 037C₁₆) = 1 : CLKi
input level = L
When transmitting:
-Transmit interrupt cause select bit (bits 0, 1 at address 03B0₁₆, bit 4 at address
037D₁₆) = 0 : Interrupts requested when data transferred from UARTi transfer buffer
register to UARTi transmit register is complete
-Transmit interrupt cause select bit (bit 0, 1 at address 03B0₁₆, bit 4 at address
037D₁₆) = 1 : Interrupts requested when data transmission from UARTi transfer reg-
ister is complete
When receiving:
-Interrupts requested when data transferred from UARTi receive register to UARTi
receive buffer register is complete.
Overrun error (Note 2)
This error occurs when the next data are ready before contents of UARTi receive
buffer register are read out
Note 1: n denotes the value 00 ₁₆ to FF₁₆ that is set to the UART bit rate generator.
Note 2: If an overrun error occurs, the UARTi receive buffer will have the next data written in.
Also, the UART receive interrupt requst bit is not set to 1 .
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