Subject: [E3-hacking] pblq 0.3.pre1

From: David Given <[email-masked]>
Date: Fri, 14 Nov 2008 22:33:24 +0000

I've uploaded the latest version, kinda, of pblq:

http://www.cowlark.com/amstrad

This is a whole lot better than 0.2 and features faster blessing code
(ripped off from pbltool, ta muchly), better protocol handling, much
more efficient flash erase, it now defaults to the right baud rates,
etc, etc.

This is mostly useful for talking to the E2. It will also talk to the
E3, but that's much less tested. In particular, the sync protocol on the
E3 is different from the E2; for some reason the E3 (or, *my* E3)
doesn't send a handshake byte after you've synced with it, the way the
E2 does, which makes figuring out when it's ready for packets rather
messy, which explains why syncing is always a bit unreliable.

It's a pre1 because my E2 died in the middle of testing. No, I don't
think pblq killed it.

-- 
┌─── ｄｇ＠ｃｏｗｌａｒｋ．ｃｏｍ ───── http://www.cowlark.com ─────
│
│ ⍎'⎕',∊N⍴⊂S←'←⎕←(3=T)⋎M⋏2=T←⊃+/(V⌽"⊂M),(V⊝"M),(V,⌽V)⌽"(V,V←1⎺1)⊝"⊂M)'
│ --- Conway's Game Of Life, in one line of APL

---

From: Dave Mills <[email-masked]>
Date: Sat, 29 Nov 2008 15:17:17 +0000

> It's a pre1 because my E2 died in the middle of testing. No, I don't
Hi David,

I've just given this version a try - no joy though. It just sits there
"Waiting for device reset..."

I am trying to talk to a fresh out of the box E2 with a simple zener
diode voltage limiter serial cable.  One thing that might be causing
problems is my USB>RS232 converter - I shall have to find a laptop with
a real serial port to try again.

cheers,
Dave

---

From: David Given <[email-masked]>
Date: Sat, 29 Nov 2008 18:53:24 +0000

Dave Mills wrote:
[...]
> a real serial port to try again.

Don't forget that the protocol requires the E2 to talk back. RS232 is
>+3V for logic 0, <-3V for logic 1, and the E2 expects TTL voltages with
0V for logic 0 and 5V for logic 1 --- so the sense is inverted with
respect to RS232. I don't think you can convert in both directions with
a simple voltage limiter.

I used a hacked mobile phone cable --- details on my website. I don't
think that specific model's in production any more, but once you know
what to look for RS232-TTL converters are reasonably easy to come by.

---

From: Dave Mills <[email-masked]>
Date: Sun, 30 Nov 2008 17:02:08 +0000

> what to look for RS232-TTL converters are reasonably easy to come by.
I'm using the paranoid serial cable from the wiki:
http://wiki.earth.li/Serial_cable_for_the_paranoid

I'll give pblq2 a try again to see if that talks to the E2, with my
setup. It didn't compile with gcc4 when I tried, then I saw your update
was out and didn't try again with pblq2.

cheers,
Dave

---

From: David Given <[email-masked]>
Date: Sun, 30 Nov 2008 19:18:33 +0000

Dave Mills wrote:
[...]
> http://wiki.earth.li/Serial_cable_for_the_paranoid

Ah --- I see the problem!

The E2 and the E3 need *different* serial cables! The E2 uses TTL, while
the E3 uses *inverted* TTL (0V for logic 1 and 5V for logic 0).

(In fact, strictly you should use a MAX232-ish circuit for the E3 as
well; it emits 0V for logic 1, which isn't <-3V as the RS232 spec
decrees, but most PC serial ports seem to cope anyway. I just plug mine
straight in with no circuitry, using a cable for an old Canon digital
camera --- sorry, can't find it to get the exact pinout; the cable, with
a 9-pin serial plug on one end and a stereo jack on the other, would
have had exactly the right pinout had I not chopped it up to look at the
wiring.)

> was out and didn't try again with pblq2.

If you're playing with an E3 you're probably better off with pbltool. It
does pretty much the same job, but is known to work on an E3, and is all
nicely streamlined into the Linux distro.