UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
311 of 362
NXP Semiconductors
UM10208
Chapter 24: LPC2800 LCD
5.7 Busy checking vs. instruction / data output
The LRS pin can be used to select between output to an instruction register and output to
a data register, or it can be used to select between reading from a status register
containing a busy bit and reading or writing to a data register. Unless the remote device
has its instruction register at the “output side” of the same address from which its status
register is read, LRS can’t be used in both ways. If the remote device has more than one
address pin used to select registers for input and output, GP output pins must be used to
drive some or all of the address pins. Wait at least 7 LCD clocks after writing to LCDIBYTE
or LCDDBYTE, and at least 22 LCD clocks after writing to LCDIWORD or LCDDWORD,
before changing such GPIO address lines for a new transfer.