Toshiba TC9314F Manual

TC9314F2003-07-03533. D/A ConverterThe D/A converter can be used for such applications as an electronic volume control that operates usinganalog voltage control.When using the D/A converter, set the DA ON bit to “1”, set the SEL0 bit to “0”, and set the SEL1 bit to“1”. This outputs, from the DA OUT pin, the D/A analog voltage corresponding to the AR0~AR5 data.Because setting data to the DA REF data 2 port (φL22) simultaneously updates the D/A conversion dataAR0~AR5, always set the AR4 and AR5 bits (φL22) last. When using the D/A converter and the A/Dconverter at the same time, control the SEL0 and SEL1 bits by software and operate by time sharing. Asthe D/A output goes to high impedance when the A/D converter is operating, connect a voltage retentioncapacitor to the output.Use the following formula to calculate the D/A output.64nVvoltageoutputD/A REF ×= (where n is the AR0~AR5 data value [decimal] 63 >= n >= 1)Note 55: The D/A output has an internal buffer. If necessary, add an external buffer.Note 56: As the D/A output range is 0 V~V DD − 1.0 V, be careful when VREF = VDD.Note 57: For D/A conversion, the string resistors are the V REF voltage divided into 64 increments.D/A Converter Structure