- entry 2024/05/12

Tea v0.09

A messed up grid.

This is happening because the day change was happening at midnight, but the schedule change appears to happen around 5am. As a result of this, the hour offsets weren't matching the day.
In order to work around this, I've added a fudge that will simply subtract 1 from "what day is today" if it's before 5am.
This code has been tested in theory, but not in reality. It's a workday tomorrow so please excuse me not wanting to stay up to 1am. In addition, the actual time of the schedule change is not known, I'm just guessing that it is 5am as that's when the daily schedule appears to start/end. Hopefully you'll all be asleep then so that won't be a problem. ☺

Complexity

Roland E-15 block diagram.

It's a bit hard to see due to being shrunk to fit, so allow me to explain that the keyboard and front panel controls (the right side of the diagram) are fed in a 68HC11 processor. It looks like the only connection between this and an H8 processor is via a MIDI switch, so it appears as if the actual keyboard and/or the front panel may translate what is happening into MIDI commands, that are then interpreted by the rest of the keyboard. That seems to be a bit of an odd way to do it, but okay...

I finally found a Service Manual for my E-16 and there are way more differences than a simple change in model number might suggest. I mean, you'd think the E-16 was a later or slightly better E-15, wouldn't you?

The E-15 has a 24SC201 sound generator hooked to two 8Mbit ROMs (that's 2MBytes), the 6811 (with an 8MHz crystal) controlling all the pokey-proddy parts, and passing MIDI data in serial format to an H8 (taking its clock from a 20MHz crystal) to perform the actual sound synthesis. MIDI out comes from the 6811, so all of the drums and such are being handled by the eight bit processor. It is, logically, two separate units in one box - the keyboard/interface part, and the sound synthesis part.

Here's the E-16.

Roland E-16 block diagram.

This is much simpler, and no longer splits the unit into two logical sections. Everything is now handled by an H8 processor clocked from a 20MHz crystal. It shares a full address and data bus with a GP4 sound generator (a Roland TC6116AF, a fairly widespread wavetable synth chip). The wave ROM is an 8Mbit part (1MByte), despite it seeming as if this device offers more voices.

This is all a bit academic as I don't use my Roland much. The primary reasons are that it uses serial MIDI which is a pain with modern machines; plus it is a rather peculiar (non-compliant) implementation of MIDI. Much easier to plug in my (USB) Yamaha that just works. But it was interesting to look to see how the devices fit together inside.

For comparison, here's the Yamaha. Sorry about the black bits. This is the sort of thing that happens when you use the simplistic photo editor on a mobile phone to manipulate screenshots...

Yamaha PSR E333 block diagram.

Your comments:

Please note that while I check this page every so often, I am not able to control what users write; therefore I disclaim all liability for unpleasant and/or infringing and/or defamatory material. Undesired content will be removed as soon as it is noticed. By leaving a comment, you agree not to post material that is illegal or in bad taste, and you should be aware that the time and your IP address are both recorded, should it be necessary to find out who you are. Oh, and don't bother trying to inline HTML. I'm not that stupid! ☺ ADDING COMMENTS DOES NOT WORK IF READING TRANSLATED VERSIONS.
 
You can now follow comment additions with the comment RSS feed. This is distinct from the b.log RSS feed, so you can subscribe to one or both as you wish.

Add a comment (v0.11) [help?] . . . try the comment feed!
		Your name
		Your email	(optional)
		Validation	Are you real? Please type 63315 backwards.
		Your comment