C8051T322-GQR Silicon Labs, C8051T322-GQR Datasheet - Page 119

• Manufacturer Part Number: C8051T322-GQR
• Description: 8-bit Microcontrollers - MCU USB-OTP-16K-LQFP32
• Manufacturer: Silicon Labs

Specifications of C8051T322-GQR

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

SFR Definition 20.1. VDM0CN: V
SFR Address = 0xFF
20.3. External Reset
The external RST pin provides a means for external circuitry to force the device into a reset state. Assert-
ing an active-low signal on the RST pin generates a reset; an external pullup and/or decoupling of the RST
pin may be necessary to avoid erroneous noise-induced resets. See Table 7.4 for complete RST pin spec-
ifications. The PINRSF flag (RSTSRC.0) is set on exit from an external reset.
20.4. Missing Clock Detector Reset
The Missing Clock Detector (MCD) is a one-shot circuit that is triggered by the system clock. If the system
clock remains high or low for more than the MCD time-out, a reset will be generated. After a MCD reset,
the MCDRSF flag (RSTSRC.2) will read 1, signifying the MCD as the reset source; otherwise, this bit reads
0. Writing a 1 to the MCDRSF bit enables the Missing Clock Detector; writing a 0 disables it. The state of
the RST pin is unaffected by this reset.
20.5. Comparator0 Reset
Comparator0 can be configured as a reset source by writing a 1 to the C0RSEF flag (RSTSRC.5).
Comparator0 should be enabled and allowed to settle prior to writing to C0RSEF to prevent any turn-on
chatter on the output from generating an unwanted reset. The Comparator0 reset is active-low: if the non-
inverting input voltage (on CP0+) is less than the inverting input voltage (on CP0-), the device is put into
the reset state. After a Comparator0 reset, the C0RSEF flag (RSTSRC.5) will read 1 signifying
Comparator0 as the reset source; otherwise, this bit reads 0. The state of the RST pin is unaffected by this
reset.
Name
Reset
Bit
5:0
Type
7
6
Bit
VDDSTAT
VDMEN
Unused
VDMEN
Name
Varies
R/W
7
VDDSTAT
V
This bit turns the V
tem resets until it is also selected as a reset source in register RSTSRC (SFR Def-
inition 20.2). Selecting the V
may generate a system reset. In systems where this reset would be undesirable, a
delay should be introduced between enabling the V
reset source. See Table 7.4 for the minimum V
0: V
1: V
V
This bit indicates the current power supply status (V
0: V
1: V
Unused. Read = Varies; Write = Don’t care.
Varies
DD
DD
R
6
DD
DD
DD
DD
Monitor Enable.
Status.
Monitor Disabled.
Monitor Enabled.
is at or below the V
is above the V
Varies
R
5
C8051T620/621/320/321/322/323
DD
DD
DD
monitor circuit on/off. The V
Monitor Control
monitor threshold.
Varies
Rev. 1.1
DD
R
4
DD
monitor threshold.
monitor as a reset source before it has stabilized
Function
Varies
R
3
DD
Varies
DD
Monitor turn-on time.
R
2
DD
DD
Monitor cannot generate sys-
Monitor and selecting it as a
Monitor output).
Varies
R
1
Varies
R
0
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