Technical information

MITSUBISHI MICROCOMPUTERS

3806 Group

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

D-A Converter

The 3806 group has two internal D-A converters (DA1 and DA2)

with 8-bit resolutions.

The D-A converter is performed by setting the value in the D-A

conversion register. The result of D-A converter is output from the

DA1 or DA2 pin by setting the DA output enable bit to “1”.

When using the D-A converter, the corresponding port direction

tus).

The output analog voltage V is determined by the value n (base

10) in the D-A conversion register as follows:

V = VREF ✕ n/256 (n = 0 to 255)

Where VREF is the reference voltage.

At reset, the D-A conversion registers are cleared to “0016”, the DA

output enable bits are cleared to “0”, and the P56/DA1 and P57/

DA2 pins are set to input (high impedance).

The D-A output is not buffered, so connect an external buffer when

driving a low-impedance load.

Set VCC to 4.0 V or more when using the D-A converter.

Fig. 20 Block diagram of D-A converter

Fig. 21 Equivalent connection circuit of D-A converter

P56/DA1

D-A1 conversion register (8)

R-2R resistor ladder

1 output enable bit

7/DA2

D-A2 conversion register (8)

R-2R resistor ladder

2 output enable bit

Data bus

REF

"0"

"1"

MSB

"0"

"1"

2R 2R

LSB

/DA1

D-A1

conversion

output enable bit