Phytec phyCORE-i.MX27, Hardware Manual

Page: 39 / 100

System Configuration
©
PHYTEC Messtechnik GmbH 2011 L-710e_5
31
6 System Configuration
Although most features of the Freescale phyCORE-i.MX27 microcontroller are configured and/or pro-
grammed during the initialization routine, other features, which impact program execution, must be
configured prior to initialization via pin termination.
6.1 System Startup Configuration
During the reset cycle the i.MX27 processor reads the state of selected controller signals to determine
the basic system configuration. The configuration circuitries (pull-up or pull-down resistors) are
located on the phyCORE module. They are already set, so no further settings are necessary.
6.1.1 Power-Up-Mode-Select (PUMS)
The Power-Management-IC (M13783) has three Power-Up-Mode-Selecets. PUMS1 and PUMS2
determine the initial setup for the voltage level of the switchers and regulators and if they get enabled
or not. With PUMS3 three different power up sequences are selectable.
The three states of the PUMS settings are:
- Pull-up (connected to VATLAS)
- Pull-down (connected to GND)
- Open (no jumper populated/left open)
For detailed information about PUMS and the power up sequence, refer to the MC13783 IC
User’s
Guide, chapter 5.3 Power up.
The i.MX27 module (PCM-038) comes with a standard Power-Up-Mode-Select (
see table below ).
Table 6: Default PUMS for i.MX27 module
PUMS1 GND
PUMS2 GND
PUMS3 Open
Note:
The i.MX27 controller has a defined power up sequence . Refer to the i.MX27 Data Sheet, chapter 3.3
Power-Up sequence.