cp2200 Silicon Laboratories, cp2200 Datasheet - Page 39

• Manufacturer Part Number: cp2200
• Description: Single-chip Ethernet Controller
• Manufacturer: Silicon Laboratories

9.2. Power-fail
When a power-down transition or power irregularity causes V
drive the /RST pin low and return the CP2200/1 to the reset state. When V
CP2200/1 will be released from the reset state as shown in Figure 14.
The power supply monitor circuit (V
every power-on reset. To prevent the device from being held in reset when V
may be deselected as a reset source (see RSTEN on page 42) and disabled (see VDMCN on page 39). It is
recommended to leave the V
9.3. Oscillator-Fail Reset
If the system clock derived from the oscillator fails for any reason after oscillator initialization is complete, the reset
circuitry will drive the /RST pin low and return the CP2200/1 to the reset state. The CP2200/1 will remain in the
reset state for approximately 1 ms then exit the reset state in the same manner as that for the power-on reset.
9.4. External Pin Reset
The external /RST pin provides a means for external circuitry to force the CP2200/1 into a reset state. Asserting the
/RST pin low will cause the CP2200/1 to enter the reset state. It is recommended to provide an external pull-up
and/or decoupling capacitor of the /RST pin to avoid erroneous noise-induced resets. The CP2200/1 will exit the
reset state approximately 4 µs after a logic high is detected on /RST.
Bit 7:
Bit6:
Bits 5–0: RESERVED. Read = varies; Write = don’t care.
VDMEN VDDSTAT Reserved Reserved Reserved Reserved Reserved Reserved 00000000
R/W
Bit7
VDMEN: V
This bit can be used to disable or enable the V
enabled and selected as a reset source following every power-on reset. If the V
disabled and then reenabled during device operation, it must be allowed to stabilize before it is
selected as a reset source. Selecting the V
generate a system reset. See Table 13 on page 42 for the minimum V
0: V
1: V
VDDSTAT: V
This bit indicates the current power supply status (V
0: V
1: V
DD
DD
DD
DD
R/W
Bit6
Monitor Disabled.
Monitor Enabled.
voltage is at or below the V
voltage is above the V
DD
Register 11. VDMCN: V
DD
Monitor Enable
Status
Bit5
DD
R
Monitor enabled and selected as a reset source at all times.
DD
Monitor) is enabled and selected as a reset source by hardware following
Bit4
R
DD
Monitor threshold.
DD
Monitor threshold.
Bit3
R
Rev. 1.0
DD
DD
Monitor Control Register
DD
Monitor as a reset source before it has stabilized will
DD
Monitor Circuit. Note: The V
Bit2
R
DD
to drop below V
Monitor output).
Bit1
R
DD
DD
drops below V
returns to a level above V
RST
, the power supply monitor will
DD
Bit0
R
Monitor turn-on time.
DD
CP2200/1
Monitor circuit is
Reset Value
RST
Address:
0x13
DD
, the V
Monitor is
DD
RST
Monitor
, the
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