Re: hex-to-LCD display chip

 

--- In cosmacelf@..., "Robert Armstrong" <bob@j...> wrote:

1 latch from Elf
(probably with a slow external clock)
One more silly queston, if you're planning to implement the
strobe/latch
in software, how wide (i.e. how many nanoseconds) is the strobe
going to
need to be for the software to see it? Especially if you use a
slow R/C
clock for your micro?

Bob
The PIC has 2 counters with external edge-triggers (an 8-bit and
16-bit). These can generate interrupts on overflow. Connect the
strobe to one, set the counter to FF (or 16-bit to FFFF), and enable
interrupts. On interrupt, copy the data (that's fast) and reset the
counter to FF.

For the LED, use the PWM output for the LED common. Set for 60 Hz,
whatever duty cycle. No need to synchronize - use the PWM from one
PIC to toggle a FET to ground, and run all the LEDs through it.
Alternatively let each digit run free.

Dave

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