Look what I found googling around... the RK3066 SDK schematics!
For those that don't know, all this flood of RK sticks is due to Rockchip handing out those schematics to OEMs, which just remove the parts that don't fit their application (for example no G-sensor or no touchpad for a TV stick).
So, for the case of most RK3066 TV sticks around it is most usual to find the following chips inside them:
Power Management Unit: Texas Instruments TPS659102
Wifi: Mediatek MT5931
Bluetooth: Mediatek MT6622 (actually in the same bundle board with the Wifi chip)
Well, those are the chips depicted in this RK3066 SDK schematic (page 16 for Wifi+BT, and page 6 indicates TPS659102, even if WM8326 is mentioned in page 4).
For the case of my Measy U2C, which has an integrated webcam, the schematic part referring to the front camera (page 15) has also been of help (even if just to know it's rigged to I2C bus 3).
However the CODEC chip used here is the RK Jetta (i.e. RK610), not the RK1000 used in my stick.
UPDATE: Please note that above schematic is different and more recent (Jan 2013) than the one already known (Feb 2012), which uses PMU WM8326, Wifi+BT RK903 (BCM40183 - Broadcom 4330 Based Chipset).
Since my stick also has an A/V out (stereo headphone connection but with TV Out, missing on above schematic), an integrated microphone and a RK1000-S A/V CODEC chip, I've found this other old schematic that shows up how that part is likely set up on page 6 of this RK2818 schematic.
Why is this important?
Because for proper Linux support it is necessary to know which RK3066 pins are connected to what pins of other chips.
So it's not enough with having the source code of the Wifi MT5931 driver in order to enable it in Linux, you must also know how it is connected to the RK3066 CPU.
Also, since I'm currently debugging the unthinkable power consumption when the stick is turned "off" (from Android and Linux, so... kernel bug or PCB design catastrophe), the TPS659102 PMU connections along with its datasheet will shed some light on it.
Hopefully with these schematics we are another step closer to better Linux support.
BTW, if you are also working on supporting TV sticks in Linux (like for example Picuntu), drop me a line, we can probably help each other!
UPDATE 2: Reverse-engineering the Measy U2C stick
From a "high-megapixel" Measy U2C PCB inspection, trying to identify the remaining (tiny) chips, and by looking for SOT23 packages in the schematics, I've identified several other discrete components of >2 pins:
- Another PM related [tiny] SOT23-6 chip, the Silergy SY8009B is U14 in the schematic (due to the nearby 3R3 inductor, or else it could've been U18) providing the VDD_LOG (1.1V) voltage that the original WM8326 regulator had (see p.4 of SDK schematic), but the TPS659102 doesn't (compare pp. 4 and 6). It's just below the MicroSD slot, marked "CU2UJ":
- One SOT23 (3 pins) BAT54RS Schottky diode marked "LD3", just below the HDMI connector.
- Two SOT23 N channel [Enh. Mode] FET components of type DMN2170U labelled "21N" and found below the A/V out (which is above the HDMI). In my opinion, from their closeness to the HDMI connector, they are replacing Q14 and Q15, marked 2SK3018 in the schematic, and required for proper screen EDID reading.
- One/two SOT23 NPN transistor L8050QLT marked "1YC" to the right of the A/V out (right through, on the other side, there is another SOT23 that I think is the same type). If it weren't because these are NPN transistors, instead of FETs, I'd say they were stereo headphone related (so close to it!) and substituting the FETs Q12 and Q13, of type APM2306, in the RK1000 related schematic above. But my electronics are so far in the past that this could be blasphemy :)
Do you think those are many SOT23 components? Well, they are much less than those on the schematic!
Some are missing because there is no LCD and some others just because the system power comes from the USB, heavily simplifying the power part (or else it'd have to generate 5V for the USB OTG port).
However there are also unpopulated parts in the PCB and I am still missing some three pin components (like USB detection interrupt).
One particular component that I fear is missing is Q17, a FET for the PMU's PMIC_SLEEP with the following significative text (p. 7): "Note: Reduce the power consumption in deep sleeping. Place it near to crystal."
Maybe the "W41M" unknown component, which is not so far from the PMU could be this Q17? I hope so!
For those that don't know, all this flood of RK sticks is due to Rockchip handing out those schematics to OEMs, which just remove the parts that don't fit their application (for example no G-sensor or no touchpad for a TV stick).
So, for the case of most RK3066 TV sticks around it is most usual to find the following chips inside them:
Power Management Unit: Texas Instruments TPS659102
Wifi: Mediatek MT5931
Bluetooth: Mediatek MT6622 (actually in the same bundle board with the Wifi chip)
Well, those are the chips depicted in this RK3066 SDK schematic (page 16 for Wifi+BT, and page 6 indicates TPS659102, even if WM8326 is mentioned in page 4).
For the case of my Measy U2C, which has an integrated webcam, the schematic part referring to the front camera (page 15) has also been of help (even if just to know it's rigged to I2C bus 3).
However the CODEC chip used here is the RK Jetta (i.e. RK610), not the RK1000 used in my stick.
UPDATE: Please note that above schematic is different and more recent (Jan 2013) than the one already known (Feb 2012), which uses PMU WM8326, Wifi+BT RK903 (BCM40183 - Broadcom 4330 Based Chipset).
Since my stick also has an A/V out (stereo headphone connection but with TV Out, missing on above schematic), an integrated microphone and a RK1000-S A/V CODEC chip, I've found this other old schematic that shows up how that part is likely set up on page 6 of this RK2818 schematic.
Why is this important?
Because for proper Linux support it is necessary to know which RK3066 pins are connected to what pins of other chips.
So it's not enough with having the source code of the Wifi MT5931 driver in order to enable it in Linux, you must also know how it is connected to the RK3066 CPU.
Also, since I'm currently debugging the unthinkable power consumption when the stick is turned "off" (from Android and Linux, so... kernel bug or PCB design catastrophe), the TPS659102 PMU connections along with its datasheet will shed some light on it.
Hopefully with these schematics we are another step closer to better Linux support.
BTW, if you are also working on supporting TV sticks in Linux (like for example Picuntu), drop me a line, we can probably help each other!
UPDATE 2: Reverse-engineering the Measy U2C stick
From a "high-megapixel" Measy U2C PCB inspection, trying to identify the remaining (tiny) chips, and by looking for SOT23 packages in the schematics, I've identified several other discrete components of >2 pins:
- Another PM related [tiny] SOT23-6 chip, the Silergy SY8009B is U14 in the schematic (due to the nearby 3R3 inductor, or else it could've been U18) providing the VDD_LOG (1.1V) voltage that the original WM8326 regulator had (see p.4 of SDK schematic), but the TPS659102 doesn't (compare pp. 4 and 6). It's just below the MicroSD slot, marked "CU2UJ":
 |
| Measy U2C close up (in case you wonder, there is nothing under the GC2035) |
- One SOT23 (3 pins) BAT54RS Schottky diode marked "LD3", just below the HDMI connector.
- Two SOT23 N channel [Enh. Mode] FET components of type DMN2170U labelled "21N" and found below the A/V out (which is above the HDMI). In my opinion, from their closeness to the HDMI connector, they are replacing Q14 and Q15, marked 2SK3018 in the schematic, and required for proper screen EDID reading.
- One/two SOT23 NPN transistor L8050QLT marked "1YC" to the right of the A/V out (right through, on the other side, there is another SOT23 that I think is the same type). If it weren't because these are NPN transistors, instead of FETs, I'd say they were stereo headphone related (so close to it!) and substituting the FETs Q12 and Q13, of type APM2306, in the RK1000 related schematic above. But my electronics are so far in the past that this could be blasphemy :)
 |
| BTW: no CPU heatsink for Measy :( |
- A SOT23 chip marked "W41M" near the upper left corner of the Wifi+BT module (the brown board) that I haven't been able to identify yet.
 |
| MT6622 BT chip and MT5931 Wifi on the brown module and single antenna |
Do you think those are many SOT23 components? Well, they are much less than those on the schematic!
Some are missing because there is no LCD and some others just because the system power comes from the USB, heavily simplifying the power part (or else it'd have to generate 5V for the USB OTG port).
However there are also unpopulated parts in the PCB and I am still missing some three pin components (like USB detection interrupt).
One particular component that I fear is missing is Q17, a FET for the PMU's PMIC_SLEEP with the following significative text (p. 7): "Note: Reduce the power consumption in deep sleeping. Place it near to crystal."
Maybe the "W41M" unknown component, which is not so far from the PMU could be this Q17? I hope so!
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