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P5040/P5020 Reference Design Board User Guide, Rev. 0
22
Freescale Semiconductor
Architecture
•
ngPIXIS FPGA injects system-level resets along with legacy COP or Aurora resets.
•
Legacy COP HRST is mapped to the P5040/P5020 POR.
•
Legacy COP SRST is mapped to the P5040/P5020 HRESET.
•
P5040/P5020 HRST is a bi-directional open drain signal; it is not monitored by ngPIXIS FPGA.
NOTE
Reset configuration input signals are ONLY sampled at the negation of
POR. Reset Configuration input pins—CFG_RCW_SRC[4...0],
CFG_SVR[1...0], CFG_GPINPUT[15...0], CFG_ENG_USE[3...0],
CFG_ELBC_ECC, CFG_DRAM_TYPE—function differently when a
device is not in a reset state.
Figure 12. Power-on Reset Sequence
Table 12. PORESET Sequence
Step
Sequence Stage
Description
1
PORESET: General
Information
1. PORESET is asserted.
2. FPGA drives CFG_RCW_SRC[4...0] and all reset configuration input signals
to P5040/P5020; see
.
3. P5040/P5020 loads RCWs.
4. FPGA drives HRESET/ PORESET to load a new RCW to the device.
P5040/P5020 loads the RCW during HRESET.
2
PORESET: During Negation
1. Sampling of input signals determines the interface to be loaded into the
device.
2. P5040/P5020 asserts HRESET throughout PORESET.
Stable CLKIN
PORESET
Min 32 CLKIN cycles
HRESET(IO)
PLLs are locked
(output)
RESET_REQ
Device ready, can start Pre-Boot
(output)
TRST
(Input)
(Input)
(Output)
(Reset Configuration Word-512 bit)
Start Load Reset Configuration
CFG Signals
Sampling point, when PORESET is negated
ASLEEP
(Reset Configuration Input Signals)
RCW
High Impedance
High Impedance