10 Aug
2011
10 Aug
'11
1:03 a.m.
On Tue, Aug 9, 2011 at 5:54 PM, Kim Phillips kim.phillips@freescale.com wrote:
On Tue, 9 Aug 2011 17:31:29 -0500 Joe Hershberger joe.hershberger@ni.com wrote:
- /* Update the local output buffer soft copy */
- gpio_output_value[ctrlr] =
- (gpio_output_value[ctrlr] & ~lineMask) | (value ? lineMask : 0);
what's the use of having a local output buffer soft copy? I don't see it being used anywhere.
It's used in the line you quoted. If other lines on the same controller are configured for open-collector, but are externally pulled low, then using the DAT register instead of the soft copy will force those to be actively grounded. To avoid this, I use a soft-copy.
-Joe