M16C80 Datasheet, PDF (187/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
22. D/A Converter
22. D/A Converter
This is an 8-bit, R-2R type D/A converter. The microcomputer contains two independent D/A converters 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. Set the
function select register A3 to I/O port, the related input peripheral function of the function select register B3
to disabled and the direction register to input mode. When the D/A output is enabled, the pull-up function of
the corresponding port is automatically disabled.
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 22.1 lists the performance of the D/A converter. Figure 22.1 shows the block diagram of the D/A
converter. Figure 22.2 shows the D/A control register.
Table 22.1 Performance of D/A converter
Item
Conversion method
R-2R method
Resolution
8 bits
Analog output pin
2 channels
Performance
Data bus low-order bits
D/A register i (8) (i = 0, 1) ^{(Address 039816, 039A16)}
R-2R resistance ladder
D/Ai output enable bit (i = 0, 1)
P93 / DA0
P94 / DA1
Figure 22.1 Block diagram of D/A converter
Rev.1.00 Aug. 02, 2005 ^{Page 176} of 329
REJ09B0187-0100