About the GAT Stand Addon Holder

The GAT Stand is a desktop addon holder with smart features.

Initial version is limited to 200mA for addons with 300mA transients. The vast majority of addons will work within these limitations.

Features (both planned and implemented)

• Holds a badge addon
  • GAT pre-standard, SAOv1, SAOv1.69bis
• Soft-switchable power to addon port with protection
• Soft-switchable power to downstream USB port
• Buttons for soft switching power
• USB connectivity to a computer to customize power schedule
• Downstream USB connectivity supports daisy chaining of holders with connectivity along the entire path
• Status LED

Specs

• MCU: CH32V203 MCU, 64K flash, 20K SRAM
• 200mA output current, 300mA transient
  • No more than 10uF apparent load
• Automatic power based on ambient light conditions
• CR1220 battery holder for settings retention and RTC

Usage

Normal mode (right most DIP switch off): - Top button toggles addon power - Bottom button toggles USB power - Soft power state is retained through power cycles if a battery is present

Autolight mode (right most DIP switch on): - Buttons do nothing - Addon and USB power will both turn off when light level is low. Addon and USB power will both turn on when light level is not low.

Left DIP Switch: LED brightness Middle DIP Switch: Disable LED

Unknown things

• USB downstream may not work due to no crystal in use. USB tolerance may not allow operation. If this is the case, an alternate protocol will need to be used.
• USB support in general is not yet implemented.
• RTC is working, but code for setting the clock and setting alarms is not yet implemented.

Firmware, Schematics

Code and schematics for the addon holder are found here:

git clone https://git.trueserve.org/trueControl/sc8-gat-stand.git

Pre-built imgaes will be available later.

3D model and acrylic cut files will be uploaded later.