16f628 LCD

[l_gaminde]

Im making a new Proto board for a 16f628 and 16f877, are there any problems using 16f628's portA for 4 bit LCD output ? other than turning on Digital.

[HenrikOlsson]

Hi,
On the 628 RA4 is open drain so it can't actively drive the output high, only pull it low. A pullup resistor is needed to be able to get a logic '1' on that pin. RA5 doesn't have any output drivers at all so it's input only.

/Henrik.

[l_gaminde]

HenrikOlsson
Thanks for your reply RA5 I did not bring out from the 16f628 to the header so ok there and RA4 is used as RS and pulled high with resistor and using A0 ~ A3 and my 4 data bits looks like Im ok

thank you for the reply
Larry