[sdiy] Alesis Midiverb eprom images

[Andre Majorel]

On 2010-11-01 19:50 +1100, Robin Whittle wrote:

> Here are the raw binary images of the EPROM which drives the DSP
> section, for the MIDIVerb in its two incarnations - a reverb device
> and an effects device (delay etc. if I recall correctly):

There were two versions of the Midiverb ?

> I think the MIDIVerb DSP section is remarkable - just an EPROM,
> standard logic chips, RAM and a DAC, with a bit of analogue circuitry.
>  It performs A to D, stereo D to A and then all the effects.  I recall
> staring at the circuit for a long time and still not being able to
> figure out how it works.

http://valhalladsp.wordpress.com/2010/08/25/rip-keith-barr/

"The DRAM required 2 addressing cycles, ROW and COLUMN, each 7
bits wide. I developed a system that fetched 2 bytes from the
EEPROM and used the lower 7 bits of each as row and column
addresses, after passing them through an 8 bit adder which
summed the last values of ROW and COL with the new ones. This
eliminated an address counter, as the code simply expressed the
next address relative to the previous address."

-- 
André Majorel http://www.teaser.fr/~amajorel/