use gruvin as base for mods?

Gruvin 9x development has now been stopped - with the development team joining up with the open9x team to produce one firmware.
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hamburger
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use gruvin as base for mods?

Post by hamburger » Thu Jan 19, 2012 9:52 pm

Hi,
for the last couple days/weeks I have been digging into the various flavours of t9x firmwares. I am trying to decide on which variant to choose as a starting point. As the changes I want to do require hardware mods, I have come to think the gruvin board with its extended ports/cpu might be ideal because I do not have to worry too much about hardware limitations from the start (radioclone warned me it already uses full capacity of hardware, so no space left for add-ons).

I want to do 3 things (my background is some MultiWii hacking):
a)
attach via TTL Serial; is that possible a color touchscreen. That device has possibility to offload some logic to its own cpu or I could use it to just display the GUI and send button events down to the t9x.
b)
attach gyro+acc 6DOF IMU to optionally steer by tilting/rotating the tx. Preferred method would be i2c.
c)
read telemetry data from model via a BT device, attach this BT via TTL Serial.

From this stem some questions I could not easily find answers for:
is the current gruvin hardware/firmware kinda stable?
How many serial ports are free to use?
How many i/o ports are free?
Is i2c usable or somehow taken already (like pins used for other purposes)?

Thanks, Hamburger

th9xer
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Re: use gruvin as base for mods?

Post by th9xer » Mon Jan 23, 2012 10:35 am

Totally spare on Gruvin V4.1 are:

8 Digital I/O pins
3 Analouge/Digital pins (with on board dividers) (+ another 4 without dividers if you don't want JTAG)

These pins also have the following hardware functions:

. One hardware serial port, will do either async or sync serial RXD2 TXD2 XCK2.
. Three PWM channels for Timer4 OC4A OC4B OC4C
. One PWM channel for Timer2 OC2B
. Clock input for Timer4 T4

Partially spare is:

Hardware I2C has a header, currently used for RTC, obviously devices are chainable.
SPI programming pins are only connected to the programming header so they are available for multiplexing.
If you don't want rotary encoders you get 3 pins back per encoder that you ditch (one of them is a hardware serial port to, giving you two free ones).

Encoder 1 is on the following hardware pins:
ICP1/PD4
OC3C/INT5/PE5
T3/INT6/PE6

Encoder 2 is on the following hardware pins:
(Best to remove C91 C92 and C94 if you want to use it as a serial port, part of RC debouncer)
XCK1/PD5
RXD1/INT2/PD2
TXD2/INT3/PD3

Think that covers it.

Cam.
Last edited by th9xer on Mon Jan 23, 2012 1:34 pm, edited 1 time in total.

th9xer
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Re: use gruvin as base for mods?

Post by th9xer » Mon Jan 23, 2012 11:07 am

Full schematic can be found here:
viewtopic.php?f=7&t=4&start=150#p1913

Cam.

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Re: use gruvin as base for mods?

Post by hamburger » Fri Jan 27, 2012 7:23 pm

thanks for the info. So I am decided. Need to recharge my paypal and order the gruvin 4.1 board (+sd board).
Surely I will come back with more questions to follow.
Cheers, Hamburger

th9xer
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Re: use gruvin as base for mods?

Post by th9xer » Mon Feb 06, 2012 9:16 pm

No problem, any questions just ask.

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