NXP Semiconductors P4080, User Manual, Page: 41 / 60

P4080 Development System User’s Guide, Rev. 0
Freescale Semiconductor 41
Configuration
6.1 Configuration Options
The P4080DS uses the OCM function in the ngPIXIS to control how the board is configured as part of the
normal power-up sequence. The OCM monitors a two-position switch, which allows selecting one of the
configuration modes shown in this table.
6.1.1 Configuration Modes
This section describes the various configuration modes.
6.1.1.1 Bypass
In bypass configuration mode, the GMSA processor is kept in reset, so no OCM software runs. No switch
settings can be changed; whatever is selected on the configuration switches is used during the
HRESETconfiguration sampling interval.
It is also possible for the system to change its own configuration registers and initiate a software-controlled
restart (“self-shmooing”), just as with previous platforms.
This mode is backwards-compatible with previous generation platforms.
6.1.1.2 Memory
In memory configuration mode, the ngPIXIS registers are initialized as in Section 6.1.1.1, “Bypass .” If the
system is not in self-shmoo mode, the OCM loads values from the SW(1:8) and EN(1:8) registers from the
I
2
C-based EEPROM storage at device address 0x55. This device is isolated and powered from the standby
power supply and is available even before the system has been powered up.
Table 18. P4080DS Configuration Options
SW_CFGOPT(0:1)
Configuration
Mode
Description
00 Bypass Switch settings control all system configurations.
No software in the OCM is executed. The following functions are NOT available:
• Real-time PVT data collection
• VCORE voltage changes
01 n/a —
10 Memory If VCTL=1 (self-shmoo is in process), no changes are made; otherwise, Pixis SW/EN
registers are loaded from external EEPROM, and for every bit in a control all system
settings, For every bit in an enable register that is set to one, the corresponding bit in a
switch register is driven onto the board during HRESET.
11 Interactive Same as “Memory” mode, except that during startup, the OCM pauses and allows the user
to alter and optionally re-write the memory with new configuration settings with a UART
connected to COM1.
If no IO is received within 20 seconds, IO is stopped and “Memory” mode is used.