User's Manual

DRAFT
4: VAM-CM interfaces
Figure 8. PCM Protocol – Mode 2 Data Format
4.2.6:Power Supply interface description
The Power supply interface contains multiple pins to share high current flow of one pin to several
pins. Additional grounding pins are spread out for different sub-interfaces.
Digital interfaces to VAM-CM processor (DM3725) are connected via level shifters. VAM terminal can
determine the interface voltage level by applying interface voltage in V_io pin (#15) of VAM-CM
system connector. V_io can be selected between 1,65V … 5,5V.
Power supply interface pins are located in VAM Control interface as described in Table 8
Pins Signal Description
#1, - #8 3v9 Power Supply for VAM-CM
3,9V (min3,6V, max 4,2V)
1,0A rms (4A peak)
#9 -
#14,
#44,
#46,
#47
GND Power Supply GND
#15 Vio I/O voltage supply for level shifters in VAM-CM
Vio voltage range 1,65V … 5,5V
#19 Ext Vrtc
supply
External backup voltage supply to enable possibility to arrange external
battery backup supply for RTC and backup features.
3,3V (maximum load 1mA)
Table 8. Power Supply interface pins
4.2.7:External VRTCSupply Functionality
Internal RTC battery is left out from the VAM-CM design. Ext Vrtc supply input is however included in
VAM system interface to allow possibility to feed external back-up voltage for VAM-CM to enable
warm start in case of long term cut off of 3v9 Supply. Internal buffer capacitors in VAM-CM will
maintain back-up voltage for 10 seconds which is meant to keep up back-up operation during short
3v9 supply cut-offs.
16:GSPS Core Module 2.0 VAM-CM HW Description
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