stc_led_clock_8k

Firmware for chinese DIY clock kits based on STC microcontrollers, for parts using devices with 8K of flash.

Hardware requirements

A DIY clock kit using the STC15W408AS microcontroller.

Other parts having 8K of flash (exactly, support for higher capacities TODO), at least 5K of EEPROM, along with a PCA module and conventional timers T0 & T2 should work fine.

Getting Started

Clone or download the repository contents.

To build and flash, you will need:

1. A working copy of sdcc installed on your machine (to build the firmware)
2. stcgal (to deliver the firmware payload onto the target device)

Execute the following commands once a USB serial adapter is connected to the ISP port of the device

cd Release
make 
stcgal -o eeprom_erase_enabled=True -t 22118.4 stc_led_clock_8k.ihx

Since significant use of the EEPROM is present, stcgal may report a protocol error on flashing the output hex file, on devices that have already written data to the EEPROM, as the EEPROM data would not be correctly programmed due to a erase cycle for the EEPROM not being performed. In this case, flashing a blank hex file, with -o eeprom_erase_enabled=True and then executing the stcgal flash command listed above is likely to resolve the problem, by enabling EEPROM erase before programming.

Features

• Time & date display (Both 24h and 12h time formats, MM/DD or DD/MM date formats, configurable leading zero suppression)
• Temperature display (Centigrade temperature scale only, offset adjustable, 0.1deg C resolution)
• Versatile alarm system
  • Maximum of seven alarms
  • Global alarm enable / disable
  • Individual alarm enable / disable
  • Alarms triggering on specific days of the week
  • Alarm length limiting
• Night light function
• Configurable automatic display scrolling (time, date, temperature, day-of-week, year)
• Configurable automatic dimming
• CRC checksumming of BBSRAM contents to detect corruption / power loss

Operation

• Menu button : Topmost switch

• Select button : Bottom switch

• To toggle the night light function (max display brightness) in the time display screen, press the select button. By default (on startup), the display is set to the maximum brightness.

• Long press on the menu and select buttons to enter the configuration menu

• Press menu to cycle between the configuration options, press select to enter a configuration section

• Use the menu and select buttons to navigate a configuration section, press or hold down the select button to change numerical / boolean values

• Long press menu to save configuration

• To reset the device, press and hold both select and menu buttons on power application.

Caveats & Bugs

• Alarm triggering is only checked for once every minute, when not in the settings menu.
• Display may exhibit slight flickering at the lowest on-time, depending on which specific seven segment display is used by the kit manufacturer.

Porting to other devices

Check out board_config.h . Simply adjust the board specific definitions and initlization functions located in that file.

Note that a common anode display is assumed. Work to support common cathode devices is in progress.

Acknowledgements

• zerog2k (Initial progress on custom firmware for these diy clocks)
• aFewBits (Alternate approach to clock firmware, configuration menus, etc)
• SparkFun Electronics (LED font table was derived from the SevSeg project)