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P4080 Development System User’s Guide, Rev. 0
50
Freescale Semiconductor
Programming Model
7.1.7
Speed Status Register (PX_SPD)
The speed status register (PX_SPD) is used to communicate the current switch-selectable settings for the
SYSCLK clock generator, one of eight preset values. This register is typically needed for software to be
able to accurately initialize timing-dependent parameters, such as those for local bus, DDR memory, I
2
C
clock rates, and more.
7.1.8
Board Configuration Register (PX_BRDCFG0)
The board configuration register (PX_BRDCFG0) controls the board configuration. Unlike other
configuration settings, those controlled by this register may be changed at any time.
Offset 0x07
Access: Read only
0
4
5
7
R
—
SYSCLK
W
Reset
0
0
0
0
0
n
n
n
Figure 32. Speed Status Register (PX_SPD)
Table 29. PX_SPD Field Descriptions
Bits
Name
Description
0–4
—
Reserved
5–7
SYSCLK
Reflects switch settings as described in
.
Offset 0x08
Access: Read/Write
0
1
2
3
4
5
6
7
R
NGI2C_ACC
PJWP_B
—
SD8X
W
Reset
0
0
0
1
0
0
0
1
Figure 33. Board Configuration Register 0 (PX_BRDCFG0)
Table 30. PX_BRDCFG0 Field Descriptions
Bits
Name
Description
0–1
—
Reserved
2
NGI2C_ACC Controls the whether the system may access the private I
2
C devices owned by the ngPIXIS device.
0 The system cannot access those devices.
1 The system may access those devices.
3
—
Reserved
4
PJWP_B
Controls whether the PromJET may be written to or not.
0 The PromJet cannot be written to.
1 The PromJet may be written to.