One option is to define a macro the application can use when needed. A macro can turn the display off with the “v off” command. First, define a particular hotspot over the entire screen, then assign this hotspot to another macro. When the user touches any location on the touch screen, the assigned macro is run. The ‘wake-up’ macro could remove the hotspot and turn the display back on with the “v on” command. A screen touch can notify the application with either a standard “x” notification from the SLCD or a custom message from the ‘wake-up’ macro. See the example macros in the file PowerSaveExampleMacros.txt.
What is the typical, worst case, and surge current requirements for the SLCD43 Module (Part Number 51-0105-01)?
The typical room temperature current is as follows, measured at 5V DC input: CASE 1 – Full bright “xbb 255”, blank screen: 238mA CASE 2 – Full bright “xbb 255”, checkerboard screen: 243mA (the checkerboard pattern alternating white and black pixels is worst-case panel power) These are typical numbers. We quote the absolute worst case (400mA) on the datasheet; it is improbable that all parts of any particular module will be the worst case. See the inrush power on applying power to the module in the image below. This surge charges the tantalum capacitors on the board. The module contains a supervisor reset chip MCP809T with a minimum delay of 150mS from power. So as long as the caps are charged in 100mS, all will be well. You could easily limit the inrush current to 400mA and be okay.
We do not have a low-power battery version at this time. Customers have used the 4.3″ display with a battery, but it is not specifically ultra-low power.
How many volts can the SLCD43 reset line take? We want to hold the reset line at 5 volts high, and set it low to reset, but weren’t sure if the board could handle it.
The RESET input is driven high (to 3.3v) by the on-board reset controller. You can drive it low through an open-collector circuit to reset the board, but you should not drive it high. If you need to, use the voltage present on J1 pin 1.