Programmers Model
ARM DUI 0447J
Copyright © 2009-2014, ARM. All rights reserved.
4-21
ID052914
Non-Confidential
4.4.14
System Configuration registers
The following System configuration registers, SYS_CF, exist:
•
SYS_CFGDATA.
•
SYS_CFGCTRL.
•
SYS_CFGSTAT.
The registers are collectively referred to as SYS_CFG registers.
The registers enable communication between the MCC and Daughterboard Configuration
Controller to read and write a variety of system parameters, for example:
•
Oscillators.
•
Voltage.
•
Current.
•
Power.
To complete a CFG transfer in your application code, implement the following pseudo code:
•
Clear the SYS_CFGSTAT Complete bit.
•
For writes, set the SYS_CFGDATA value with your data value. For example, to set an
oscillator to 50MHz, write
50000000
to this register.
•
Set the SYS_CFGCTRL register with the correct function and destination value. For
example, to read from the Motherboard oscillator 1, set the SYS_CFGCTRL register to
0x80100001
:
—
Start =
1
—
Write =
1
—
DCC =
0
—
Function =
1 (OSC)
—
Site =
0 (MB)
—
Position =
0
—
Device =
1
, oscillator 1.
•
Wait for the SYS_CFGSTAT Complete bit to be set to indicate that the read or write
transfer has completed.
•
For reads, you must read the SYS_CFGDATA register to read the returned data.
Config SYS_CFGDATA
The SYS_CFGDATA Register characteristics are:
Purpose
Holds the data value to be written or read during communication across
the SPI interface between the MCC and a Daughterboard Configuration
Controller.
Usage constraints
There are no usage constraints.
Configurations
Available in all configurations.
Attributes
See
Table 4-3 on page 4-8
.
Table 4-17
shows the register bit assignments.
Table 4-17 SYS_CFGDATA Register bit assignments
Bits
Name
Description
[31:0]
CFG data
32-bit configuration data register