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CY8C28xxx PSoC Programmable System-on-Chip TRM, Document No. 001-52594 Rev. *G
System Resets
30.4.4
Reset Details
Timing and functionality details are summarized in
.
shows some of the relevant signals for IPOR,
PPOR, and XRES, while
shows signaling for WDR and IRES.
30.5
Power Consumption
The ILO block drives the CLK32K clock used to time most
events during the reset sequence. This clock is powered
down by IPOR, but not by any other reset. The sleep timer
provides interval timing.
While POR or XRES assert, the IMO is powered off to
reduce start-up power consumption.
During and following IRES (for 64 ms nominally), the IMO is
powered off for low average power during slow supply
ramps.
During and after POR or XRES, the bandgap circuit is pow-
ered up.
Following IRES, the bandgap circuit is only powered up
occasionally, to refresh the sampled bandgap voltage value.
This sampling follows the same process used during sleep
mode.
The IMO is always on for at least one CLK32K cycle, before
CPU reset is deasserted.
Table 30-1. Details of Functionality for Various Resets
Item
IPOR (Part of POR)
PPOR (Part of POR)
XRES
WDR
Reset Length
While POR = 1
While PPOR = 1, plus
30-60
s (1-2 clocks)
While XRES = 1
30
s (1 clock)
Low Power (IMO Off) During Reset?
Yes
Yes
Yes
No
Low Power Wait Following Reset?
No
No
No
No
CLK32K Cycles from End of Reset to
CPU Reset Deasserts
a
a. CPU reset is released after synchronization with the CPU Clock.
512
1
8
1
Register Reset
(See next line for CPU_SCR0,
CPU_SCR1)
All
All, except PPOR does not
reset Bandgap Trim
register
All
All
Reset Status Bits in CPU_SCR0,
CPU_SCR1
Set PORS,
Clear WDRS,
Clear IRAMDIS
Set PORS,
Clear WDRS,
Clear IRAMDIS
Set PORS,
Clear WDRS,
Clear IRAMDIS
Clear PORS,
Set WDRS,
IRAMDIS unchanged
Bandgap Power
On
On
On
On
Boot Time
b
b. Measured from CPU reset release to execution of the code at Flash address 0x0000.
2.2 ms
2.2 ms
2.2 ms
2.2 ms
Summary of Contents for CY8C28 series
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