C8051F350DK Silicon Laboratories Inc, C8051F350DK Datasheet - Page 80

• Manufacturer Part Number: C8051F350DK
• Description: DEV KIT FOR F350/351/352/353
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F350DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F35x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F350
• Silicon Family Name: C8051F35x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F350, 351, 352, 353
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1083

C8051F350/1/2/3
The Comparator hysteresis is software-programmable via its Comparator Control register CPT0CN. The
user can program both the amount of hysteresis voltage (referred to the input voltage) and the positive and
negative-going symmetry of this hysteresis around the threshold voltage.
The Comparator hysteresis is programmed using Bits3–0 in the Comparator Control Register CPT0CN
(shown in SFR Definition 9.1). The amount of negative hysteresis voltage is determined by the settings of
the CP0HYN bits. As shown in Figure 9.2, settings of 20, 10 or 5 mV of negative hysteresis can be pro-
grammed, or negative hysteresis can be disabled. In a similar way, the amount of positive hysteresis is
determined by the setting the CP0HYP bits.
Comparator interrupts can be generated on both rising-edge and falling-edge output transitions. (For Inter-
rupt enable and priority control, see Section “12. Interrupt Handler’ on page 105). The CP0FIF flag is set to
logic 1 upon a Comparator falling-edge occurrence, and the CP0RIF flag is set to logic 1 upon the Com-
parator rising-edge occurrence. Once set, these bits remain set until cleared by software. The Comparator
rising-edge interrupt mask is enabled by setting CP0RIE to a logic 1. The Comparator0 falling-edge inter-
rupt mask is enabled by setting CP0FIE to a logic 1.
The output state of the Comparator can be obtained at any time by reading the CP0OUT bit. The Compar-
ator is enabled by setting the CP0EN bit to logic 1, and is disabled by clearing this bit to logic 0.
Note that false rising edges and falling edges can be detected when the comparator is first powered on or
if changes are made to the hysteresis or response time control bits. Therefore, it is recommended that the
rising-edge and falling-edge flags be explicitly cleared to logic 0 a short time after the comparator is
enabled or its mode bits have been changed. This Power Up Time is specified in Table 9.1 on page 85.
80
(Programmed with CP0HYP Bits)
Positive Hysteresis Voltage
INPUTS
OUTPUT
VIN+
VIN-
CIRCUIT CONFIGURATION
Positive Hysteresis
CP0-
CP0+
VIN+
VIN-
Disabled
V
Figure 9.2. Comparator Hysteresis Plot
OL
V
OH
+
_
CP0
Positive Hysteresis
Maximum
OUT
Rev. 1.1
Negative Hysteresis
Disabled
Negative Hysteresis
(Programmed by CP0HYN Bits)
Maximum
Negative Hysteresis Voltage