C8051F987-GMR Silicon Labs, C8051F987-GMR Datasheet - Page 86

• Manufacturer Part Number: C8051F987-GMR
• Description: 8-bit Microcontrollers - MCU 8kB 512B RAM
• Manufacturer: Silicon Labs

Specifications of C8051F987-GMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051F99x-C8051F98x
5.9.
The voltage reference MUX is configurable to use an externally connected voltage reference, the internal
voltage reference, or one of two power supply voltages (see Figure 5.10). The ground reference MUX
allows the ground reference for ADC0 to be selected between the ground pin (GND) or a port pin
dedicated to analog ground (P0.1/AGND).
The voltage and ground reference options are configured using the REF0CN SFR described on page 88.
Electrical specifications are can be found in the Electrical Specifications Chapter.
Important Note About the V
inputs. When using an external voltage reference or the internal precision reference, P0.0/VREF should be
configured as an analog input and skipped by the Digital Crossbar. When using AGND as the ground
reference to ADC0, P0.1/AGND should be configured as an analog input and skipped by the Digital
Crossbar. Refer to Section “21. Port Input/Output” on page 213 for complete Port I/O configuration details.
The external reference voltage must be within the range 0  V
reference must be at the same DC voltage potential as GND.
86
4 .7 F
B ypass C apacitors
R ecom m ended
G N D
V D D
Voltage and Ground Reference Options
+
R 1
R eference
E xternal
V oltage
C ircuit
0 .1 F
Figure 5.10. Voltage Reference Functional Block Diagram
P 0.1/A G N D
P 0.0/V R E F
V D D
REF
G N D
and AGND Inputs: Port pins are used as the external V
Rev. 1.1
R egulated D igital S upply
H igh S peed R eference
R E F 0C N
Internal 1.65 V
Internal 1.8V
REF
 VDD and the external ground
E N
T em p S ensor
R E F G N D
00
01
10
11
0
1
REF
and AGND
(to A D C )
(to A D C )
V R E F
G round
Input
A D C
M ux