M30222 Datasheet, PDF (167/237 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

deUvnedloepr ^ment
Specifications in this manual are tentative and subject to change
MITSUBISHI MICROCOMPUTERS
M30222 Group
Rev. G
D-A Converter
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
D-A Converter
This is an 8-bit, R-2R type D-A converter. The microcomputer contains two independent D-A convert-
ers of this type. D-A conversion is performed when a value is written to the corresponding D-A register.
Bits 0 and 1 (D-A output enable bits) of the D-A control register decide if the result of conversion is to be
output. Do not set the target port to output mode if D-A conversion is to be performed.
Output analog voltage (V) is determined by a set value (n : decimal) in the D-A register.
V = Vref X n/ 256 (n = 0 to 255)
Vref : reference voltage
Table 1.55 lists the performance of the D-A converter. Figure 1.135 shows the block diagram of the D-
A converter. Figure 1.136 shows the D-A control register. Figure 1.137 shows the D-A converter
equivalent circuit.
Table 1.55. Performance of D-A converter
Item
Conversion Method
Resolution
Analog output pin
Performance
R-2R
8 bits
2 channels
Data bus low-order bits
D-A register0 (8)
(Address 03D816)
R-2R resistor ladder
D-A0 output enable bit
P93/DA0
D-A register1 (8)
(Address 03DA16)
R-2R resistor ladder
D-A1 output enable bit
P94/DA1
Fig. 1.135. Block diagram of D-A converter
1-168