M16C/62 Group DATASHEET

UART2 Special Mode Register 2Mitsubishi microcomputersM16C / 62 GroupSINGLE-CHIP 16-BIT CMOS MICROCOMPUTERBit 4 of the UART2 special mode register 2 (address 037616) is used as the UART2 initialization bit.Setting this bit to "1", and when the start condition is detected, the microcomputer operates as follows.(1) The transmission shift register is initialized, and the content of the transmission register is transferredto the transmission shift register. This starts transmission by dealing with the clock entered next as thefirst bit. The UART2 output value, however, doesn’t change until the first bit data is output after theentrance of the clock, and remains unchanged from the value at the moment when the microcomputerdetected the start condition.(2) The reception shift register is initialized, and the microcomputer starts reception by dealing with theclock entered next as the first bit.(3) The SCL wait output bit turns to "1". This turns the SCL pin to "L" at the falling edge of the ninth bit ofthe clock.Starting to transmit/receive signals to/from UART2 using this function doesn’t change the value of thetransmission buffer empty flag. To use this function, choose the external clock for the transfer clock.Bit 5 of the UART2 special mode register 2 (037616) is used as the SCL pin wait output bit 2. Setting thisbit to "1" with the serial I/O specified allows the user to forcibly output an "L" from the SCL pin even ifUART2 is in operation. Setting this bit to "0" frees the "L" output from the SCL pin, and the UART2 clockis input/output.Bit 6 of the UART2 special mode register 2 (037616) is used as the SDA output disable bit. Setting this bitto "1" forces the SDA pin to turn to the high-impedance state. Refrain from changing the value of this bitat the rising edge of the UART2 transfer clock. There can be instances in which arbitration lost detectionflag is turned on.147