Hi Michael, Tony,

> > also is there a minimum clock speed for writing to an lcd module.
>
> yes, most lcd modules have a busy bit that can be read or a command
> execution time of 40us for most commands and upto 200us for clear
> display commands.

Tony was asking about a minimum write speed.  You have described the
maximum write speed limitations.

The LCD displays are essentially static in I/O operation and you can
write to it at any convenient speed as long as the rise times on the
signals are reasonable.

There are minimum pulse widths that also cannot be exceeded which
prevents direct connection to processor busses without wait states
as well as the command execution limits Michael mentioned.

Cheers
--
Kalle Pihlajasaari   kalle@ip.co.za   http://www.ip.co.za/ip
Interface Products   P O Box 15775, DOORNFONTEIN, 2028, South Africa
+ 27 (11) 402-7750   Fax: 402-7751    http://www.ip.co.za/people/kalle