Differences

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

--- boards:ecb:scg:start [2020/09/27 10:49] – Revision from 2020-09-27
+++ boards:ecb:scg:start [2026/06/15 12:24] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 /* Imported from Wayback Machine
    Original URL : https://retrobrewcomputers.org/doku.php?id=boards:ecb:scg:start
-   Snapshot date: 2020-09-27
+   Snapshot date: 2025-10-15
    Generator    : wayback-archiver
 */
-====== ECB Sprite Color Graphics ======
 Video Display Interface Board
@@ Line 40: / Line 38: @@
 So maybe that is something for the next iteration…
+From Adam Dewis: “It turns out 9128/9118s and such designed with 4-Bit DRAM have bidirectional data pins instead of the multiplexed address/data out and data-in bus on the 9918 which (necessitated by 1-bit DRAMs having separate data in and out pins). After going cross eyed at the schematics for a while I noticed U9 latches data out onto the SRAMs bidir data bus. As the 9128 is also bidir this latch isn't needed if you substitute a TMS9118/9128 chip. I thought I would pass this along as it is not mentioned on the wiki, it took me a fair amount of digging to locate this information, and other than some characters being repeated in text mode these the TMS9128 appears to be an acceptable substitute for the TMS9918.”
 A 2Mhz crystal is specified for the sound chip clock but on board dividers can be configured to use a higher frequency crystal. Also common serial and colour burst frequency crystals can be used depending on your need for frequency accuracy and compatibility.
@@ Line 83: / Line 83: @@
 <code code>
--7:  Audio Oscillator / 8
+-8:  Audio Oscillator / 1
--9:  Audio Oscillator / 2
+* 5-7:  Audio Oscillator / 2
-* 6-8:  Audio Oscillator
 -10: Audio Oscillator / 4
+-9:  Audio Oscillator / 8
+(Corrected 29/11/2021)
 </code>