Datasheet

MPC5200 Data Sheet, Rev. 4
Electrical and Thermal Characteristics
Freescale Semiconductor16
3.3.3 Resets
The MPC5200 has three reset pins:
•PORRESET - Power on Reset
•HRESET - Hard Reset
•SRESET - Software Reset
These signals are asynchronous I/O signals and can be asserted at any time. The input side uses a Schmitt
trigger and requires the same input characteristics as other MPC5200 inputs, as specified in the DC
Electrical Specifications section. Table 14 specifies the pulse widths of the Reset inputs.
Notes:
1. For PORRESET
the value of the minimum pulse width reflects the power on sequence. If PORRESET is asserted afterwards
its minimum pulse width equals the minimum given for HRESET
related to the same reference clock.
2. The t
VDD_stable
describes the time which is needed to get all power supplies stable.
3. For t
lock,
refer to the Oscillator/PLL section of this specification for further details.
4. For t
up_osc,
refer to the Oscillator/PLL section of this specification for further details.
5. Following the deassertion of PORRESET
, HRESET and SRESET remain low for 4096 reference clock cycles.
6. The deassertion of HRESET
for at least the minimum pulse width forces the internal resets to be active for an additional 4096
clock cycles.
NOTE
As long as VDD is not stable the HRESET
output is not stable.
Table 13. SYS_XTAL_IN Timing
Sym Description Min Max Units SpecID
t
CYCLE
SYS_XTAL_IN cycle time.
1
NOTES:
1
CAUTION—The SYS_XTAL_IN frequency and system PLL_CFG[0-6] settings must be chosen such that the
resulting system frequencies do not exceed their respective maximum or minimum operating frequencies. See the
MPC5200 User Manual [1].
28.6 64.1 ns A2.1
t
RISE
SYS_XTAL_IN rise time. — 5.0 ns A2.2
t
FALL
SYS_XTAL_IN fall time. — 5.0 ns A2.3
t
DUTY
SYS_XTAL_IN duty cycle (measured at V
M
).
2
2
SYS_XTAL_IN duty cycle is measured at V
M
.
40.0 60.0 % A2.4
CV
IH
SYS_XTAL_IN input voltage high 2.0 — V A2.5
CV
IL
SYS_XTAL_IN input voltage low — 0.8 V A2.6
Table 14. Reset Pulse Width
Name Description Min Pulse Width
Max Pulse
Width
Reference Clock SpecID
PORRESET
Power On Reset t
VDD_stable
+t
up_osc
+t
lock
— SYS_XTAL_IN A3.1
HRESET
Hardware Reset 4 clock cycles — SYS_XTAL_IN A3.2
SRESET
Software Reset 4 clock cycles — SYS_XTAL_IN A3.3