Differences

This shows you the differences between two versions of the page.

--- pocket386:lcd_controller [2024/05/17 12:19] – agiri
+++ pocket386:lcd_controller [2024/05/19 22:38] (current) – natalie
@@ Line 7: / Line 7: @@
 The manufacturer has not posted schematics or a PCB design file for the LCD drive board, so we must reverse engineer it to learn more about how it works.
-Special note: I found firmware source for the Book 8088's LCD controller [[https://github.com/zhblue/RTD2660|here]]. It's unclear if this is the same as what's used in the Pocket 386. I ignored this and blackbox RE'd everything
+Special note: I found firmware source for the Book 8088's LCD controller [[https://github.com/zhblue/RTD2660|here]]. It's unclear if this is the same as what's used in the Pocket 386. I ignored this and blackbox RE'd everything. A dump of the LCD controller's flash for safekeeping is available [[index|on the main Pocket 386 page here]].
 ===== Hardware =====
@@ Line 19: / Line 19: @@
 ==== Signals ====
-  * **Red wire:** Active-low enable line for the LCD. Bringing this high will disconnect the H/Vsync and RGB lines from the LCD controller, through U7 (TS5V330 analog switch) and U8/U9 (74LVC1G125 buffers). Pulled up to the 3v3 reg's Vin through R5 (4k7)
+  * **Red wire:** Active-low enable line for the LCD, used in external VGA mode. Bringing this high will disconnect the H/Vsync and RGB lines from the LCD controller, through U7 (TS5V330 analog switch) and U8/U9 (74LVC1G125 buffers). Pulled up to the 3v3 reg's Vin through R5 (4k7)
   * **Black wire:** TTL serial data from the keyboard controller. This is uni-directional to the LCD controller. As far as I know, the KBC is driving it at 5V levels. Tends to float around 4V when driven high. Pulled up to 3.3v through R20 (4k7)
@@ Line 64: / Line 64: @@
 The OSD also randomly goes corrupt in various ways. Sometimes the first time you open the OSD or S-OSD it will already be corrupt and unreadable. It's unclear why this happens... software bugs, power supply glitches, ...?
+===== PCB Shots =====
+{{ :pocket386:img20240516053820.jpg?300 |}} {{ :pocket386:img20240516053841.jpg?300 |}} {{ :pocket386:img20240516053848.jpg?300 |}}
 ===== Acknowledgements =====
-Thanks girlmux for their assistance.
+Thanks caela for your assistance.