Re: [Sdcc-user] Help: 8051 to LCD (4bit)

[Gernot F. <g....@gm...>]

On Mon, 16 May 2005, you wrote:
> can anybody check what I am doing wrong. I try to interface LCD (4bit=20
> mode) to AT89S53. The code is in assembly.
>=20
> Note: 8bit mode works fine, the electrical schema should be correct.
>=20
> Information about schema and code can be found at
>=20
> http://www.ece.ubc.ca/~andreyv/8051/

You dont have pullups on the P0 of the AT89S53 in the IO-mode.

It could be that the 8-bit code only works because you have a 0xff-write
instruction one instruction bevore reading.

p.s. I have minimak quick and dirty working code for 4-bit lcd if you wan=
t.

--=20
MFG Gernot