您看到的问题是由数字驱动程序的关闭时间引起的。
您可以
试验时间,但最重要的是避免你看到的那种涂抹,
您需要在数字驱动程序更改时短暂关闭段驱动程序。
该
正常的刷新顺序可能是:
禁用所有段驱动程序以及所有数字驱动程序。
等待段驱动程序关闭时间(可能与数字驱动程序相比较短,
特别是如果它们直接连接到FPGA)。
启用下一个数字驱动。
等待任何额外的数字驱动器关闭时间。
为当前数字启用段驱动程序。
上面的序列循环遍历所有数字。
在一个系统中,数字驱动程序不能同时被禁用,您必须至少
从更改数字选择到禁用时禁用段驱动程序
之前的数字驱动程序已关闭。
此外,刷新率非常高(10赫兹的KHz
如果不这样做,将会产生线电容的次要影响
在切换数字驱动程序之前关闭段驱动程序。
这可能发生
由于LED没有开漏段线路的电容
关闭并允许线路超过导通电压。
HTH,
的Gabor
消息由gszakacs于01-16-2010 10:47 PM编辑
- Gabor
以上来自于谷歌翻译
以下为原文
The problem you are seeing is caused by the turn-off time of the digit drivers. You can
experiment with timing, but the bottom line is that to avoid the sort of smearing you see,
you need to shut off the segment drivers briefly while the digit drivers change. The
normal sequence for refresh might be:
disable all segment drivers as well as all digit drivers.
Wait for segment driver shut-off time (probably short compared to digit driver,
especially if they connect directly to FPGA).
Enable next digit driver.
Wait for any additional digit driver shut-off time.
Enable segment drivers for the current digit.
The above sequence loops through all digits.
In a system where digit drivers cannot all be disabled at once, you must at least
disable the segment drivers from the time you change the digit select until the
previous digit driver has shut off. Also at very high refresh rates (10's of KHz
and above) there will be secondary effects of line capacitance if you don't
turn the segment drivers off BEFORE switching the digit drivers. This can happen
due to the capacitance of the open-drain segment lines when the LED has not
shut off and allowed the line to rise above the turn-on voltage.
HTH,
Gabor
Message Edited by gszakacs on 01-16-2010 10:47 PM-- Gabor