[Arm-netbook] Improving the wiki, build and test processes for allwinner kernel and ubuntu images for the Mele A1000/A2000

[Henrik Nordström]

sön 2012-06-03 klockan 21:01 +0000 skrev Matthew Boyd:

> I did make an SD card adaptor, though I think I trimmed it just a bit too much 
> and managed to have it wiggle just enough to blow out one of the ports because 
> now the tablet recognizes an uSD is installed, but does not tell me anything is 
> on it.

Ouch.

> I can still get the tx side off, though all I have been able to see is 
> when it starts booting the kernel, have not gotten a peep out of u-boot or 
> bImage (depending on which version I have loaded up at the time).

Is your u-boot modified for SD-console?

Stock u-boot do not use the SD pins for serial.

> I was 
> figuring on trying to tap straight off of the test points on the motherboard by 
> the A10 that by schematics and location on the A10 should be the serial TX and  
> RX, and JTAG ports.

Yes, if you can then it's hightly recommended to use those for serial.
It's different pins from the SD-card slot, and is normally configured
for serial & jtag.

Identifying the serial pads should be easy. First, order from bottom of
the chip is serial, jtag, so serial TX/RX is the bottommost two pads
unless they have done very strange wiring of the traces. But it's hard
to say which is which. Connect GND & VCCio, then use the RX cable (the
pin where your USB UART receives data) to look for the TX pad (where the
A10 transmits data). The other one is RX.


> I was figuring on attaching them to a uSD to SD adaptor 
> that I could mount into the device without being to obtrusive, though I can 
> only get the pads narrowed down to a 50/50 shot on each of the group of 3.

Group of 3?

Serial is 2

JTAG is 4.

The order of the pins on the A10 these pads connect to is
  | 
  | MS  CK  (JTAG)
  | DO  DI
  |  -   -  (TWI, not wired to these pads)
  | TX  RX  (SERIAL)
  |

So bottom two should be the serial pads. But a bit of guesswork which is
which.

Regards
Henrik