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RE: General IO Port A?


GPIO A bit 0-3 is used for a button, the LED etc. Refer to the
developer board schematics
If you want to use GPIO you have three options:

1. Use the parallel port pins (GPIO port G). You can find an example in
2. Use the GPIO port A. The transceiver for COM 2 must be removed.
3. Use the GPIO port B. The transceiver for COM 1 must be removed.

>When i try to set the direction of the GPIO A using register 
>R_PORT_PA_DIR, then bool failure.
>the program line : *R_PORT_PA_DIR = 0x00; //ALL PINS AS INPUT
>in the module_init.

The boot up may fail due to a collision on the GPIO port A (e.g.
you try to write to a button).


-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com]On">mailto:owner-dev-etrax@xxxxxxx.com]On
Behalf Of Eric Tang
Sent: Wednesday, June 05, 2002 7:34 AM
To: dev-etrax
Subject: General IO Port A?

Dear ALL,

	I try to use the GPIO Port A, but i have got some problems,
	Can you all give me some directions?
	First, I can't find where the GPIO A is located in the board.
	It seems that the COM2 Female is using GPIO A (4,5,6,7), so 
	if i use the GPIO A, then i need to disable the COM2 Debug Port??
	And where is the 0-3 pins?

	When i try to set the direction of the GPIO A using register 
	R_PORT_PA_DIR, then bool failure.
	the program line : *R_PORT_PA_DIR = 0x00; //ALL PINS AS INPUT
	in the module_init.