D-A Converter; Fig. 4.5.7 D-A Converter Block Diagram; Table 4.5.4 Relationship Between Contents Of D-A Conversion Register And Output Voltage "V - Renesas 7200 Series User Manual

4.5.5 D-A converter

M37220M3-XXXSP/FP has 2 D-A converter with 6-bit resolution. Figure 4.5.7 shows the D-A converter
block diagram.

Fig. 4.5.7 D-A converter block diagram

D-A conversion is performed by setting the value in
the DA conversion register. The result of D-A
conversion is output from the DA pin by setting "1"
to the DA output enable bit of the port P3 output
mode control register (bits 2 and 3 at address 00CD
The output analog voltage V is determined with the
value n (n: decimal number) in the DA conversion
register.
n
V=V (n= 0 to 63)
CC
64
The DA output does not build in a buffer, so connect
an external buffer when driving a low-impedance
load.
Data bus
DA1 conversion register
6
(address 00DE
16
Resistor ladder
DA1 output enable bit
P3 /A-D5/DA1
0
).
16
7220 Group User's Manual
M37220M3-XXXSP/FP
4.5 Functional description
DA2 conversion register
6
) (address 00DF
Resistor ladder
DA2 output enable bit
P3 /A-D6/DA2
1
Table 4.5.4 Relationship between contents of D-A conversion
register and output voltage "V"
A-D control register
bit 5 bit 4 bit 3 bit 2
0 0 0 0
0 0 0 0
0 0 0 0
: : : :
1 1 1 1
1 1 1 1
1 1 1 1
)
16
Output
voltage "V"
bit 1 bit 0
0/64 V
0 0
1/64 V
0 1
2/64 V
1 0
:
: :
61/64 V
0 1
62/64 V
1 0
63/64 V
1 1
CC
CC
CC
CC
CC
CC
4-17