RE: [Gumstix-users] roboAudio-th

[Joseph W. <sj...@wi...>]

Thanks,  Let me explain what I want to do first.
=20
I need to connect AX-12 servo to one TTL UART port. =20
Is UART-0, UART-1 TTL level or 3.3V?
=20
AX-12 servo takes full duplix signal.  Where can I get the cireuit to =
merge TxD and RxD line?
=20
Yes,  I am thinking of trying the roboaudio by itself. can you tell me =
more the In System Programming ?
=20
Thanks
=20
Joseph
=20

________________________________

From: gum...@li... on behalf of Dave =
Hylands
Sent: Wed 3/1/2006 10:44 AM
To: gum...@li...
Subject: Re: [Gumstix-users] roboAudio-th



Hi Joseph,

> Thanks, I find those 7 files but it didnt't solve my question because =
my
> background is too week.  I want to find out first is the pin lay out.
> B00037.top.png has the top view of roboaudio.  And tell me the topleft =
is
> PWM but I don't know which one is power which one is ground which one =
is
> signal.

I'm at work and don't have my roboaudio in front of me, so I'll
possibly elaborate a bit more when I get home tonight.

On the regular robostix, there are some labels on the back side of the
board to help out. I don't recall with the roboaudio.

I'm guessing that the PWM block is the same as on the regular
robostix, and that ground is the outside row of pins, V_MOTOR is the
middle row of pins, and the inside row of pins are the signals.

> And the next is motor.  For what kind of motor?  What are those two
> pins?  Power and ground?

The MOTOR pins are actually V_MOTOR, for connecting up a separate
motor supply. Even servo motors draw more current than the robostix
power supply can source, and you often want to run the servos at a
different voltage than +5, so a separate power connector was provided.
On the regular robostix there's a jumper to the regular +5, I'll have
to check what's on the roboaudio.

As a general rule, you can't connect any type of motor directly to the
robostix, but you can connect a motor controller. Servos have built-in
motor controller, so they work out OK. Any other type of motor is
going to require an H-Bridge (or other motor controller).

> Then GPIO, which is signal which is ground?

I think that the little white square in each corner of the silkscreen
is pin 1. On the GPIO_5V_B block (see Sheet 2 of the schematic) there
is no ground.

> Next is ATMEGA?  What is it?  How to use it?

That's ADC_ATMEGA, which are 8 ADC's (analog to digital converters)
connected to the ATMega128. There's sample code posted (see links from
the Robostix-Programming page)

> Next is audio.  Why 6 pins? 5.1 Channel? which is which?

See Sheet 5 of the schematic. Looks like a ground (pin 4) Stero Line
in (pins 2 & 6), Stereo out (pins 1 & 5), and VREFDRV (not sure -
check the datasheet on the UCB1400).

> 16 pins in UARTS,  What are they?

Well there's a 4 pin TTL UART from the gumstix (STUART - ttyS2). There
are also 2 UARTs from the ATMega128 and an i2c (which connects to both
the gumstix and atmega)/

> What is ISP?

That's the In System Programming header for programming the atmega if
you're going to use the roboaudio by itself.

> What is the 4 pins GUMSTIX for?

Thats the console from the gumstix (als a UART - ttyS0)

This page describes many of the signals (but for the robostix)
http://gumstix.org/tikiwiki/tiki-index.php?page=3DRobostix-I%2FO

I'll see about adding a section which formats it in the connector
order that they appear in for the roboaudio.

The PWM, UARTS, gumstix, and ISP connectors are identical for the
roboaudio and the robostix.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/


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