examples: hd44780 responds on falling edge of E pin

The example itself works both ways, but the actual HD44780 chip
processes data on the falling edge - see the data sheet.

diff --git a/examples/parts/hd44780.c b/examples/parts/hd44780.c
index 144cbfc..8fe194c 100644 (file)
--- a/examples/parts/hd44780.c
+++ b/examples/parts/hd44780.c
@@ -340,8 +340,8 @@ hd44780_pin_changed_hook(
        b->pinstate = (b->pinstate & ~(1 << irq->irq)) | (value << irq->irq);
        int eo = old & (1 << IRQ_HD44780_E);
        int e = b->pinstate & (1 << IRQ_HD44780_E);
-       // on the E pin rising edge, do stuff otherwise just exit
-       if (!eo && e)
+       // on the E pin falling edge, do stuff otherwise just exit
+       if (eo && !e)
                avr_cycle_timer_register(b->avr, 1, _hd44780_process_e_pinchange, b);
 }