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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
Intelligent I/O (Serial I/O)
279
Clock synchronous serial I/O mode (group 2)
Table 1.23.17 gives specifications for the group 2 clock synchronous serial I/O mode.
Table 1.23.17. Specifications of clock synchronous serial I/O mode
Item
Specification
Transfer data format
Transfer data length:
Variable length (group2)
Transfer clock
When internal clock is selected, the transfer clock in the single waveform output
mode is generated.
_ Transfer speed is determined when the base timer is reset by the ch0 WG function
Transfer rate (bps) = base timer count source (frequency) / (k+2)
k : values set to WG register 0
_ Transfer clock is generated by ch2 single phase WG function
Ch3 WG register = (k+2)/2 (Note 1)
When external clock is selected
_ Transfer rate (bps) = Clock input to ISCLK pin (Note 2)
Transmission start condition To start transmission, the following requirements must be met:
_ Transmit enable bit = “1”
_ Write data to SI/O transmit buffer register
Reception start condition
To start reception, the following requirements must be met:
_ Receive enable bit = “1”
_ Transmit enable bit = “1”
_ Write data to SI/O transmit buffer register
When transmitting
_ When SI/O communication buffer register is empty, transmit interrupt cause select
bit = “0”
_ When transmission is completed, transmit interrupt cause select bit = “1”
When receiving
_ When data is transferred to SI/O receive buffer register
Error detection
Overrun error
This error occurs when the next data is ready before the contents of SI/O receive
buffer register are read out
Select function
LSB first/MSB first selection
When transmission/reception begins with bit 0 or bit 7, it can be selected.
Transmit/receive data polarity switching
_ This function is reversing ISTxD pin output and ISRxD pin input.
(All I/O data level is reversed.)
Data transfer bit length
_ Transmission data length can be set between 1 to 8 bits
Note 1: When the transfer clock and transfer data are transmission, transfer clock is set to at least 6 divi-
sions of the base timer clock. Except this, transfer clock is set to at least 20 divisions of the base
timer clock.
Note 2: Transfer clock is set to at least 20 divisions of the base timer clock.
Interrupt request
generation timing