D-A CONVERTER
13.2 Block description
13.2.1 D-A control register
Figure 13.2.2 shows the structure of the D-A control register.
Pin DAi (i = 0, 1) serves as the analog voltage output pin of the D-A converter. Since pin DAi is equipped
with no internal buffer amplifier, it is necessary to connect a buffer amplifier externally to pin DAi, if this
pin is needed to be connected with a low-impedance load.
Pin DAi is multiplexed with an analog input pin, external interrupt input pin, and trigger input pin in the pulse
output port mode. When any of the D-Ai output enable bits is set to “1” (output enabled), the corresponding
pin is used only as pin DAi, not as any other multiplexed input/output pin (including a programmable I/O
port pin).
b7 b6 b5 b4 b3 b2 b1 b0
D-A control register (Address 9616)
Bit
0
Bit name
Function
0: Output is disabled.
At reset R/W
0
RW
RW
—
D-A
D-A
0
1
output enable bit
1: Output is enabled. (Notes 1, 2)
output enable bit
0: Output is disabled.
1: Output is enabled. (Notes 1, 2)
0
1
Undefined
7 to 2
Nothing is assigned.
Notes 1: Pin DAi is multiplexed with an analog input pin, external interrupt input pin, and trigger input pin in the pulse output port mode.
When a D-Ai output enable bit = “1” (in other words, output is enabled.), however, the corresponding pin cannot function as
any other multiplexed input/output pin (including a programmable I/O port pin).
2: When not using the D-A converter, be sure to clear this bit to “0.”
Fig. 13.2.2 Structure of D-A control register
(1) D-Ai output enable bits (Bits 0, 1)
Setting any of the D-Ai output enable bits to “1” (output enabled) allows the corresponding pin DAi to
output D-A converted analog voltage, regardless of the contents of the corresponding bits of the port
P7 direction register.
13.2.2 D-A register i (i = 0, 1)
Each pin DA outputs the analog voltage corresponding to the value loaded in D-A register i. Figure 13.2.3
i
shows the structure of D-A register i.
b7
b0
D-A register i (i = 0, 1) (Addresses 9816, 9916)
At reset
0
Bit
Function
R/W
RW
7 to 0 Any value in the range from 0016 through FF16 can be set (Note), and this
value will be D-A converted and will be output.
Note: When not using the D-A converter, be sure to clear the contents of these bits to “0016.”
Fig. 13.2.3 Structure of D-A register i
7906 Group User’s Manual Rev.2.0
13-3
RENESAS [ RENESAS TECHNOLOGY CORP ]
