Page 128 Epson Research and Development
Vancouver Design Center
S1D13504 Hardware Functional Specification
X19A-A-002-18 Issue Date: 01/01/30
13 Power Save Modes
Two Power Save Modes have been incorporated into the S1D13504 to accommodate the important
need for power reduction in the hand-held devices market. These modes are hardware suspend and
software suspend.
13.1 Hardware Suspend
• Register read/write disallowed.
• Memory read/write disallowed.
• LCD outputs are forced low (see Note 1 of Section 13.4,
“Pin States in Power Save Modes”
on
page 129).
• LCDPWR forced to Off state.
• CRT outputs are disabled.
• If suspend mode CBR refresh is selected, all internal modules and clocks except the Memory I/F
are shut down.
• If suspend mode self-refresh or no-refresh is selected, all internal modules and clocks are shut
down.
13.2 Software Suspend
• Register read/write allowed except for RAMDAC registers.
• Memory read/write disallowed.
• LCD outputs are forced low (see Note 1 of Section 13.4,
“Pin States in Power Save Modes”
on
page 129).
• LCDPWR forced to Off state.
• CRT outputs are disabled.
• If suspend mode CBR refresh is selected, all internal modules and clocks except the Host Bus I/F
and the Memory I/F are shut down.
• If suspend mode self-refresh or no-refresh is selected, all internal modules and clocks except the
Host Bus I/F are shut down.
