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P4080 Development System User’s Guide, Rev. 0
42
Freescale Semiconductor
Configuration
The OCM transfers data from the EEPROM into the ngPIXIS SW/EN registers, as shown in this table.
The OCM examines the LSB of byte 0x08, and transfers either “Set A” (LSB = 0) or “Set B” (LSB = 1).
In all cases, when the registers have been loaded during reset configuration, wherever an EN register has
a bit set to “1”, the corresponding bit in a “SW” register is used to replace the selected switch setting. For
example, if all EN(1:8) registers are set to all ones, no external switch settings is used, so the system is
purely EEPROM-configured. This allows a system cost reduction by eliminating all but one of the (fairly
expensive) DIP switches. Conversely, if all EN(1:8) registers are set to all zeros, the register settings are
unchanged and the external switch settings are used.
During memory configuration mode, the OCM is still running code. The target system may communicate
with it via message passing; see
,” for details.
6.1.1.3
Interactive
In interactive configuration mode, the OCM prints a message to the COM1 serial port (115200, 8/N/1) and
waits up to 20 seconds for a keypress. During this time, if the system is powered up, it pauses until this
Table 19. OCM Configuration Data Format
I
2
C EEPROM
Description
ngPIXIS Register
Source Addresses
Destination Address
0x00 – 0x03
EEPROM header
—
0x08
Set Selection
bit 3=1:
Use VCORE value
bit 3=1:
Do not use VCORE
bit 0(lsb)=0: Use Set A
bit 0(lsb)=1: Use Set B
—
0x20..0x3F
Set A:
SW1, EN1
SW2, EN2
SW3, EN3
SW4, EN4
SW5, EN5
SW6, EN6
SW7, EN7
SW8, EN8
SW(x)
EN(x)
20
21
22
23
24
25
26
27
28
29
2A
2B
2C
2D
2E
2F
0x40..0x5F
Set B:
SW1, EN1
SW2, EN2
SW3, EN3
SW4, EN4
SW5, EN5
SW6, EN6
SW7, EN7
SW8, EN8
SW(x)
EN(x)
40
41
42
43
44
45
46
47
48
49
4A
4B
4C
4D
4E
4F
0x70, 0x71
VCORE output code (if enabled)
PMBus output code (MSB first)
0xA0, 0xA1
ngPIXIS register edits.
Ends on values of 0x00 or 0xFF
Address, then Data