SAB80C517-M16 SIEMENS [Siemens Semiconductor Group], SAB80C517-M16 Datasheet - Page 87

• Manufacturer Part Number: SAB80C517-M16
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

The SFR DAPR (see figure 7-29) is provided for programming the internal reference voltages
V
of 1/16 of the external reference voltages (
to 3 specify
between the internal reference voltages
converter. This means, for example, in the case where
at least four steps difference between the internal reference voltages
The values of
DAPR (.3-.0) is the contents of the low-order nibble, and DAPR (.7-.4) the contents of the high-order
nibble of DAPR.
Figure 7-29
Special Function Register DAPR (Address DA H )
D/A converter program register. Each 4-bit nibble is used to program the internal reference
voltages. Write-access to DAPR starts conversion.
Semiconductor Group
V
with DAPR (.3-.0) < C H ;
V
with DAPR (.7-.4) > 3 H ;
V
with DAPR (.3-.0) < 13;
V
with DAPR (.7-.4) > 3;
INTAREF
INTAGND
INTAREF
INTAGND
INTAREF
0DA H
and
=
=
=
=
V
V
V
V
AGND
AGND
AGND
AGND
V
V
lNTAGND
V
lNTAGND
Programming of
IntAGND
+
+
+
+
DAPR (.3-.0)
DAPR (.7-.4)
DAPR (.3-.0)
DAPR (.7-.4)
. For this purpose the internal reference voltages can be programmed in steps
, while bits 4 to 7 specify
and
16
16
16
16
V
IntAREF
V
(
(
(
(
INTAREF
are given by the formulas:
V
V
V
V
AREF
AREF
AREF
AREF
–
–
–
–
V
V
V
V
V
AGND
AGND
AGND
AGND
V
AREF
lNTAREF
)
)
)
)
V
88
–
INTAREF
Programming of
V
and
AGND
On-Chip Peripheral Components
. A minimum of 1 V difference is required
V
) by four bits each in register DAPR. Bits 0
V
AREF
INTAGND
is 5 V and
for proper operation of the A/D
V
INTAGND
V
INTAREF
V
AGND
is 0 V, there must be
and
DAPR
V
INTAGND
.