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- this page deals with connecting an lph 7508 (using pollin's display module kit) to a parallel port and drive it using
serdisplib - i'm not responsible for the content of external web pages
- external web pages will generally open in separate browser windows or tabs
- english is not my native language. please keep that in mind (corrections of english grammar and formulations are very welcome!)
- email: mrwastl at users.sourceforge.net
lph 7508 display module kit:
description
lph 7508 display modules are controlled using an on-board controller sed1560.
| specifications | |
|---|---|
| resolution | 100x64 |
| colours | monochrome |
| controller | sed1560 |
| backlight | yes |
| adjustable contrast | yes, programmable |
| dimensions | module: 77 x 64 mm, display area: 35 x 22 mm (pollin manual) |
| name in serdisplib | LPH7508 (example:
serdisp_init(sdcd, "LPH7508", ""); ) |
some images
![[lph7508 display module kit: assembled]](images/lph7508_display_kit.jpg) |
|
| fully assembled lph 7508 display kit | |
![[lph7508 test image]](images/lph7508_testserdisp.jpg) |
![[lph7508 graphlcd output]](images/lph7508_graphlcd.jpg) |
| lph7508 showing a test image | output generated by graphlcd |
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connecting an lph 7508 display module to the parallel port:
intro
lph 7508 was connected using pollin's 'lc-display module-kit'. so the wiring was 'pre-defined'.
addressing
anomaly of lph 7508
sed1560 supports a max. resolution of 132x65, but lph7508 display modules only use 100 x 64.
the last line is used for displaying symbols (support and explanations will be added in a future version).
unlike one might expect, the first column is not 0, but 32. so every column address has to be shifted by 32.
pages vs. rows
the display is organised in colums and pages: 8 pixel-rows are combined to a so called page.
as only whole bytes can be transferred to the display, a single pixel cannot be changed without knowing its 7 'neighbour' pixels.
so a display buffer was introduced in the library. pixel changes are all done in this buffer and in a separate step only changed 'page bytes' are transferred (using an optimising algorithm) to the display.
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passing options through serdisp_init():
intro
using the third parameter of
common information about passing options and customisable wiring can be found in a separate document.
serdisp_init(), driver specific options and custom wiring can be set.common information about passing options and customisable wiring can be found in a separate document.
examples:
serdisp_init(sdcd, "LPH7508", "ROTATE=90;INVERT=YES");
options
| identifier | short | remark | default |
|---|---|---|---|
| ROTATE | ROT | rotate display (1 == 180 degrees) | 0 |
| INVERT | INV | invert display | 0 |
| DELAY | delay after each write/read operation.
0 .. no delay
1 .. one call of gettimeofday()
>1 .. delay at least x nanoseconds
| 2 | |
| CONTRAST | set display contrast | 5 | |
| BACKLIGHT | BG | switch background light on or off | 0 |
| WIRING | WIRE | pre-defined or customisable wiring | 2 |
ranges, aliases
| identifier | range | aliases |
|---|---|---|
| ROTATE | 0, 1, 90, 180, 270 | YES=180, NO=0, TRUE=180, FALSE=0 |
| INVERT | 0, 1 | YES=1, NO=0, TRUE=1, FALSE=0 |
| DELAY | >= 0 | NONE=0 |
| CONTRAST | [0, 10] | |
| BACKLIGHT | 0, 1 | YES=1, NO=0, TRUE=1, FALSE=0, ON=1, OFF=0 |
pre-defined wiring definitions
| identifier | numeric id | protocol | description |
|---|---|---|---|
| ParDTPollin | 2 | PAR | Pollin Wiring for LPH7508 display module kit, parallel data transfer |
display signals
| identifier | description | mandatory |
|---|---|---|
| D0 - D7 | 8 bit wide data bus | * |
| A0 | data or command | * |
| CS | chip select input, active low | * |
| RW | read/write signal (read: high, write: low) | * |
| RESET | reset signal, active low; optional if wired to a hardware reset circuit |
annotations
- serdisplib driver sed156x supports more than one different types of displays.
- only wiring 2 (or "
ParDTPollin") is applicable for lph 7508 display module kits (the proper wiring is set by default by serdisplib when using display name "LPH7508"). - no backlight support at the momemt
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links:
| data sheets | |||
|---|---|---|---|
| sed1560 controller | data sheet for SED 1560 series | (english) | sed1560.pdf |
| lph7508 display module | data sheet for LPH 7508 display module | (german) | LPH7508-1.pdf |
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