Title: Using AMD G-Series Modules with Xtreme/CPU & Qseven Carriers
Keywords: Xtreme/CPU, Qseven, AMD, G-Series, Modules Compatibility
Date: 2012/10/15
KDB: KDB-331
Revision: 0.01
Author: MF
Distribution: External
Introduction
This knowledge base entry discusses some limitations of using AMD G-series modules with Connect Tech’s QCG001 and QCG002 carriers.
Currently the following AMD G-Series based modules exist:
Display Limitations
VGA Not Supported
The QCG001 and QCG002 offer two display interfaces: LVDS and VGA. The VGA interface is based on a SDVO (Serial Digital Video Out) to VGA converter IC (Chrontel CH7317B)
Intel Atom based modules expose an SDVO interface, while the AMG G-Series expose a HDMI interface
The Qseven interface specification reuses the same pins for the HDMI / DisplayPort / SDVO interfaces (as shown in Table 1).
Therefore, the VGA interface will be unavailable when using the AMD series
Pin | SDVO | DisplayPort | HDMI |
131 | SDVO_BCLK+ | DP_LANE3+ | TMDS_CLK+ |
133 | SDVO_BCLK- | DP_LANE3- | TMDS_CLK- |
137 | SDVO_GREEN+ | DP_LANE1+ | TMDS_LANE1+ |
139 | SDVO_GREEN- | DP_LANE1- | TMDS_LANE1- |
143 | SDVO_BLUE+ | DP_LANE2+ | TMDS_LANE0+ |
145 | SDVO_BLUE- | DP_LANE2- | TMDS_LANE0- |
132 | SDVO_INT+ | ||
134 | SDVO_INT- | ||
138 | SDVO_FLDSTALL+ | DP_AUX+ | |
140 | SDVO_FLDSTALL- | DP_AUX- | |
144 | SDVO_TVCLKIN+ | ||
146 | SDVO_TVCLKIN- | ||
149 | SDVO_RED+ | DP_LANE0+ | TMDS_LANE2+ |
151 | SDVO_RED- | DP_LANE0- | TMDS_LANE2- |
153 | HDMI_HPD# | ||
150 | SDVO_CTRL_DAT
3.3V CMOS Open Drain |
HDMI_CTRL_DAT
3.3V CMOS Open Drain |
|
152 | SDVO_CTRL_CLK
3.3V CMOS Open Drain |
HDMI_CTRL_CLK
3.3V CMOS Open Drain |
|
154 | DP_HPD# |
Table 1: Qseven Pinout
Potential for damage to converter IC
In addition to the feature reduction, there is a potential for damage, when plugging the an AMD G-series module into a QCG001 or QCG002
- HDMI outputs are essentially being attached SDVO inputs
- Differential SDVO pairs are AC coupled differential signals. Therefore, there is not a specific DC signal level.
o Differential signaling voltage VDIFF = 800 mV (2x VTX DIFF P-P=400mV)
- HDMI signals are DC coupled TMDS (Transition-minimized differential signaling); which is terminated to 3.3V.
- If the modules HDMI interface is idling at ground (0V), then there should be no long term damage to the CH7317B.
- If the modules HDMI interface is idling at 3.3V, there could be damage
- The CH7317B can tolerate up to 3.3V on its I2C interface (SDVO_CTRL_DAT and SDVO_CTRL_CLK).
o The QCG001 and QCG002 have 5.6K pull-up resistors to 2.5V; the module will likely have 3.3V 100K pull-up resistors. If this resistor value is less than 100K; there could be issues.
conga-QAF default settings
The conga-QAF has two Display Channels , Display Channel 0 Output defaults to LVDS & Display Channel 1 Output defaults to HDMI. There is also a Boot Display Device setting, which defaults to Auto.
With carriers that only have LVDS display capabilities and are attached to a LVDS display with no EDID capabilities – the module might not boot with a display. If the LVDS display unit does not have EDID capabilities (identifying resolution and colors to the BIOS) ; the BIOS settings will need to be manually changed first in another carrier with HDMI capabilities.
For example, if using the conga-QEVAL carrier with the conga-LDVI (DVI to LVDS converter) – the BIOS settings Local Flat Panel Type had to be changed From Auto (default) To WXGA 1280×768 1×24.
End of KDB-331