[Arm-netbook] pinouts, gpio, expansion header

Iliya Georgiev ikgeorgiev at gmail.com
Mon Jan 9 19:27:27 GMT 2012


2012/1/9 lkcl luke <luke.leighton at gmail.com>

> On Mon, Jan 9, 2012 at 3:20 AM, Bari Ari <bari at onelabs.com> wrote:
> > My understanding is that the FIR interface is muxed with UART2 and
> > supports SIR, CIR,MIR and FIR.
> >
> > I'll be sure to go over all the muxed pins and let everyone chime in
> > before we finish the board layouts to make them as flexible as possible.
>
>  i've been going over the pinouts and documented the options here, if
> anyone would like to help go over this:
>
>  http://rhombus-tech.net/allwinner_a10/orders/
>  http://rhombus-tech.net/allwinner_a10/pinouts/
>
>  attached is a first revision (diagram)
>
>    * 2pins: 1x USB-2
>    * 8pins: 5-pin AC97 shared with 8-pin I2S Signals.
>    * 2pins: PWM0 (PB2) and PWM1 (PI13)
>    * 2pins: IR_TX and IR_RX (also GPIOs, one of which is EINT16)
>    * 4pins: TV-Out
>    * 4pins: 4-wire Resistive Touchscreen
>    * 20pins: 2x LVDS
>
>  almost all of those can be muxed to general-purpose IO, giving about 34
> GPIOs
>
>  then, also, by putting the other RGB/TTL (not the LVDS-capable one)
> onto the 68-pin connector it would be possible to flip those pins over
> to an IDE (PATA) port.
>
>  i still haven't worked out what the GPIO pins should be.  definitely
> more of the EINTNN pins.  possibly one of the SD/MMCs, probably one of
> the SPIs: i haven't put one of those out anywhere, at all.  probably
> one of the UARTs as well.
>
>  hmmm... PI10 through to PI21 seem to be good candidates:
>
> # C17 SPI0_CS0/UART5_TX/EINT22/PI10
> # D17 SPI0_CLK/UART5_RX/EINT23/PI11
> # C16 SPI0_MODI/UART6_TX/EINT2/PI12
> # D16 SPI0_MISO/UART6_RX/EINT25/PI13
> # C15 SPI0_CS1/PS2_SCK1/TCLKIN0/EINT26/PI14
> # D15 SPI1_CS1/PS2_SDA1/TCLKIN1/EINT27/PI15
> # E17 SPI1_CS0/UART2_RTS/EINT28/PI16
> # E16 SPI1_CLK/UART2_CTS/EINT29/PI17
> # E15 SPI1_MOSI/UART2_TX/EINT30/PI18
> # D14 SPI1_MISO/UART2_RX/EINT31/PI19
> # E14 PS2_SCK0/UART7_TX/HSCL/PI20
> # E13 PS2_SDA0/UART7_RX/HSDA/PI21
>
> and maybe these:
> # A7 UART0_TX/IR1_TX/PB22
> # B7 UART0_RX/IR1_RX/PB23
>
> and, if nothing else, probably these:
> # C8 TWI2_SCK/PB20
> # C7 TWI2_SDA/PB21
>
> although if there are 2 left, it might be worthwhile doing analog
> audio out, somehow, even if it means a bit of extra circuitry.
>
> it's tricky because bizarre as it sounds we're running out of pins to
> choose from! :)  pingroups A, C, D and S are already taken up.  the
> ones in the "other" group are hard-wired and not GPIO capable.
>
> thoughts anyone?
>
>
>  btw no i do *not* think it would be a good idea to have the
> LVDS-capable port on the 68-pin connector.  not only would it then not
> be possible to conveniently get access to the PATA port, but also it
> would risk people going "oh look!  LVDS!  let's make a
> cheapo-motherboard that doesn't bother to respect EOMA-compliance".
>
>  to be successful, standards have to be absolutely non-optional: it's
> enough of a risk to have these multiplexing options on the very first
> CPU card.
>
>  if that's not clear enough, allow me to go through it.  what happens
> if LVDS is available as an "option" alongside RGB/TTL?
>
>  a) motherboards get created which have to be capable of detecting
> either LVDS _or_ RGB/TTL capable CPU cards.  the cost has therefore
> just gone up.
>
>  b) *all* CPU cards *must* now have circuitry (if the CPU doesn't have
> the exact same pinouts as the Allwinner A10) which flips LVDS _or_
> RGB/TTL onto the 68-pin connector.  the cost has therefore gone up.
>
>  either way, putting LVDS and RGB/TTL onto the 68-pin connector
> actually, far from providing nice benefits, actually destroys the
> entire project's viability.  for the sake of a $1 IC (in higher-cost
> products anyway).
>
>  l.
>
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>

I looked at the pinouts desription in:

 http://rhombus-tech.net/allwinner_a10/pinouts/

And more specifically in pin group D. Will the Smart Card (SIM Card)
Interface continue to co-exist as multiplexed function along with RGB/TTL
interface? After the decision to multiplex the RGB/TTL with PATA interface
I wondered if there will be spare pins for multiplexing the Smart Card (SIM
Card).
As for the necessity of Smart Card (SIM Card) Interface, it may be utilized
in:

1. Consumer devices like mobile devices, where SIM card may be used.
2. Industrial devices like security access devices, ATMs and etc.

I make this comments from business point of view, not taking into account
all technical considerations.

Iliya
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