ST2204 datasheet(9/24 Pages) SITRONIX

9 / 24 page

ST2204

Ver 0.6

9/24

2008/11/10

8.. C

HIIP

P--S

T L

GIIC

C ((C

L))

The ST2204 builds in one chip-select signal ( CS0 ) for

embedded 512K bytes mask ROM and six chip-select signals

multiplexed with PD5~0 of Port-D which are used to select

external devices on the address and data bus. There are two

options for the first 512K bytes memory which are controlled by

MMD pin. Tie MMD to ground to select normal mode and

enable internal ROM for the first 512K bytes memory. Connect

MMD to chip-select of an external device to select emulation

mode and disable internal ROM. After reset cycles, MMD

changes to an output and outputs chip-select signal CS0 .

Refer to FIGURE 8-1 for two connections of different modes.

Two bits CSM[1:0] of port miscellaneous register (PMCR)

select four modes of CSL which define the memory size of

each external chip-select. If CSM0 equals “1”, chip-select

signal CS6 changes to be address signal A23 to make one

single device of 16M bytes at CS5 possible. The address

range of CSx of higher number follows the range of previous

one of lower number.

Note: Write “1” to bit of port direction control

function-select register PFD to activate the

designated chip-select signal.

A. Normal Mode

B. Emulation Mode

FIGURE 8-1 Connections Of MMD/ CS0

ST2204 Datasheet(PDF) 9 Page - Sitronix Technology Co., Ltd.