ARM7 which is differences between fast GPIO and low GPIO

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hbaocr

Joined: 13 May 2007
Posts: 247
Helped: 15
Location: Hochiminh City university of technology (VietNam)

03 Oct 2007 15:01 fast gpio

hello,all friend
I'm studying ARM7 LPC2148, which is differences between fast GPIO and low GPIO
about way to use , about function ??

vhn

Joined: 20 Sep 2006
Posts: 82
Helped: 5

04 Oct 2007 5:39 plc2148 fast gpio

Hi hbaocr,
Legacy GPIO registers are known as "slow" GPIOs and the GPIO ports with enhanced features are known as "fast" GPIOs in ARM7 terminology. A different set of registers have to be programmed if you need to use fast GPIOs. For backward compatibility, some ports can still be accessed as slow GPIOs.
The fast GPIOs generally are more responsive in nature. It is claimed that these enhanced ports are around 3.5 times faster when compared to their legacy counterparts.

Regards,

bobcat1

Joined: 10 Jul 2002
Posts: 1118
Helped: 48

04 Oct 2007 17:58 lpc fast-gpio

Hi

The fast GPIO came with silicon rev 01 and can toggel the I/O line as fast as 15 MHz

The slow GPIO can access the I/O pin slower at about 3.5 MHz

All the best

Bobi

hbaocr

Joined: 13 May 2007
Posts: 247
Helped: 15
Location: Hochiminh City university of technology (VietNam)

05 Oct 2007 0:28 how to set fast gpio in arm7

thank all my friend very much
but How can i set pin to fast GPIO mode

vhn

Joined: 20 Sep 2006
Posts: 82
Helped: 5

05 Oct 2007 16:09 arm microcontroller gpio ioclr

Hi hbaocr,
First you need to select the port pin functionality as a GPIO using PINSEL registers. Further the direction has to be controlled by using FIOxDIR register. And to control the output we should use FIOxSET and FIOxCLR instead of simple IOSET / IOCLR registers that correspond to the slow GPIOs.

Regards,

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05 Oct 2007 16:09 Ads

kannan.k

Joined: 17 Jan 2006
Posts: 25
Helped: 1
Location: chennai, India

05 Oct 2007 19:41 fast gpio ports

Hi hbaocr,

In addition to what vhn has specified you will also have to set the SCS register to enable the fast IO for port0 and port1.

hope this helps.
cheers
-K