b8de35658f
* Put something on screen * Use the 32bit watch_date_time repr to pass from JS * Implement periodic callbacks * Clear display on enabling * Hook up watch_set_led_color() to SVG (green-only) * Make debug output full-width * Remove default Emscripten canvas * Implement sleep and button clicks * Fix time zone conversion bug in beats-time app * Clean up warnings * Fix pin levels * Set time zone to browser value (if available) * Add basic backup data saving * Silence format specifier warnings in both targets * Remove unnecessary, copied files * Use RTC pointer to clear callbacks (if available) * Use preprocessor define to avoid hardcoding MOVEMENT_NUM_FACES * Change each face to const preprocessor definition * Remove Intl.DateTimeFormat usage * Update shell.html title, header * Add touch start/end event handlers on SVG buttons * Update shell.html * Update folder structure (shared, simulator, hardware under watch-library) * Tease out shared components from watch_slcd * Clean up simulator watch_slcd.c inline JS calls * Fix missing newlines at end of file * Add simulator warnings (except format, unused-paremter) * Implement remaining watch_rtc functions * Fix button bug on mouse down then drag out * Implement remaining watch_slcd functions * Link keyboard events to buttons (for keys A, L, M) * Rewrite event handling (mouse, touch, keyboard) in C * Set explicit text UTF-8 charset in shell.html * Address PR comments * Remove unused directories from include paths
83 lines
3.2 KiB
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83 lines
3.2 KiB
ReStructuredText
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SLCD Synchronous driver
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=======================
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An LCD display is made of several segments (pixels or complete symbols) which
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can be block light or let light through. In each segment is one electrode
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connected to the common terminal (COM pin) and one is connected to the segment
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terminal (SEG pin). When a voltage above a certain threshold level is applied
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across the liquid crystal, it will change orientation and either let light
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through or block it.
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The driver supports segment on/off/blink, animation and character display.
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Each segment has a unique int32 segment id which is used by the driver. The id is
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combined by common number(COM) and segment number(SEG), the COM and SEG start from 0.
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The unique segment id is calculated by this formula: (COM << 16) | SEG
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For example a 8(coms)*8(segments)SLCD, the unique segment id for segment should be
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+-----+-----+---------+
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| COM | SEG | ID |
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+-----+-----+---------+
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| 0 | 0 | 0x00000 |
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+-----+-----+---------+
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| 1 | 0 | 0x10000 |
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+-----+-----+---------+
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| 7 | 7 | 0x70007 |
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+-----+-----+---------+
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Segment ID can be calculated using the pre-defined macro SLCD_SEGID(com, seg).
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For character display, the "segment character mapping table" and "character mapping table"
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should be setup in configuration. The driver have no API to setup/change those
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mapping setting.
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There are two pre-defined "segment character mapping table" in this driver, 7 segments
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and 14 segments. The 7 segment character mapping can display 0-9 and a-f, the 14
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segments character mapping can display 0-9, A-Z and some special ASCII, for more
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details please refer to hpl_slcd_cm_7_seg_mapping.h and hpl_slcd_cm_14_seg_mapping.h.
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Application can also adjust this mapping table in the configuration header file,
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to add more character mapping or remove some unused character.
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The "character mapping" is used to setup each character in SLCD display screen.
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The driver supports multiple character mapping, the max number varies on different
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MCU/MPU. For example if an LCD display screen has five "7-segments character" and
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eight "14-segments character", and the MCU support max 44 characters setting, then
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the 13 character should be setup in configuration. Application can select any
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position from those 44 characters setting to save those 13 character.
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The index of character setting will be used in the driver API. For example:
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five "7-segments character" setting to 0 to 4 and eight "14-segments character" setting
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to 10 to 17. Then the application can use index from 0 to 4 to display the
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"7-segments character" and use index from 10 to 14 to display "14-segments character".
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Features
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--------
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* Initialization and de-initialization
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* Enabling and Disabling
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* Switching segment on/off
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* Set segment blink
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* Autonomous animation
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* Character display
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Applications
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------------
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* SLCD display control, segment on/off/blink
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* Play battery animation, running wheel, wifi signal, etc.
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* Display Time Clock by 7 segments character mapping
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* Display ASCII character by 14 segments character mapping
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Dependencies
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------------
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* SLCD capable hardware
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Concurrency
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-----------
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N/A
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Limitations
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-----------
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Known issues and workarounds
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----------------------------
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N/A
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