A clone 506 cable for the Autostar 494/Autostar Aux bus
This page devoted to providing DIY build info and tech details of the Aux bus and Meade 506 functionality and augmenting that capability.
If anyone has an interest in building one of these but do not want to get into buying a PIC programmer, etc, I’ll program your PIC if desired, cost, a 2 – for – 1, for each one or two PIC programmed (and tested) you supply one PIC of same type (16F627 or 16F628 is cheaper, about $3.35) and supply stamped padded return envelope for shipping back. See link for ‘major parts list’ below. Email me if any interest: astrogene1000_stuff (AT) yahoo.com. I’ll also update your PIC as the code moves forward, just email me and send it back with original paperwork and stamped padded envelope, hence the 2-for-1 ‘cost’, one can be in transit J
I am going to keep trying for the 1244 focuser co-existence problem, it may not be real but an artifact of the 2-to-1 4 pin adapter I have.
Reliable download fully functional
Updated 6/5/2008
Basic 506 clone +
Functional clone of 1244 focuser into the ‘506’ ala the lx200/APM909 reticule port interface +
CCD port multi speed guiding capabilities into the ‘506’ ala lx200/APM909
Mix and match features based upon HW options
Source code available for non-commercial use, click me
(the parts list on the above page is superceded by the list below)
Schematic added, click for larger view
The same schematic is used for a 506, augmented 506 or 909 clone with guider and focuser
Just different parts are populated and different code added
Parts list
Jameco parts numbers
|
Common
pieces: |
Part # |
Qty |
Unit $ |
Total $ |
|
|
|
|
PIC16F628 |
246756 |
1 |
3.35 |
3.35 |
|
|
|
|
18 pin
socket |
65585 |
1 |
0.65 |
0.65 |
|
|
|
|
|
|
|
|
|
|
|
|
|
CRY,OSC,20MHz |
27932 |
1 |
2.15 |
2.15 |
|
|
|
|
14 pin
socket |
37197 |
1 |
0.44 |
0.44 |
|
|
|
|
|
|
|
|
|
|
|
|
|
RESISTOR
1k OHM |
31237 |
1 |
0.99 |
0.99 |
|
|
|
|
|
|
|
|
|
|
|
|
|
CAP,TANT, 10uF |
94080 |
1 |
0.31 |
0.31 |
|
|
|
|
CAP,CERM .01uf |
15231 |
10 |
0.067 |
0.67 |
|
|
|
|
|
|
|
|
|
|
|
|
|
78L05 5V
100ma TO-92 |
51182 |
1 |
0.29 |
0.29 |
See below
if Guider is added |
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Serial
interface - - 506 clone + debug of
909 if desired: |
|
|
|
|
|||
|
MAX202 |
142535 |
1 |
2.65 |
2.65 |
|
|
|
|
16 pin
socket |
37402 |
1 |
0.47 |
0.47 |
|
|
|
|
9PinSubD |
614504 |
1 |
2.05 |
2.05 |
|
|
|
|
CAP,CERM
0.1uf |
151118 |
10 |
0.15 |
1.5 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Guider
pieces - 909 and 506: |
|
|
|
|
|
|
|
|
RESISTOR
10k OHM |
30058 |
1 |
0.99 |
0.99 |
|
|
|
|
MODULAR
JACK,6P6C |
124039 |
1 |
1.25 |
1.25 |
|
|
|
|
Switches for
enable and rate - micro type, no current handling required |
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
Focuser
pieces - 909 and 506 |
|
|
|
|
|
|
|
|
L293D H
DRIVER |
1341966 |
1 |
2.69 |
2.69 |
|
|
|
|
16 pin
socket |
37402 |
1 |
0.47 |
0.47 |
|
|
|
|
CAP 100uf |
607700 |
1 |
0.26 |
0.26 |
|
|
|
|
2N4401,NPN |
38421 |
10 |
0.08 |
0.8 |
|
|
|
|
2N4403,PNP |
38447 |
10 |
0.047 |
0.47 |
|
|
|
|
10k
resistors |
691104 |
100 |
0.01 |
1 |
Not required if Guider is added |
||
|
78M05 5v
500ma TO-2 |
20 192233 |
1 |
0.22 |
0.22 |
Regulator if Focuser is added |
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Plus
wire, connector, box, etc |
|
|
|
|
|
|
|
Update
6/4/2008:
Added functional clone of 1244 focuser into the ‘506’ ala the lx200/APM909 reticule port interface.
Added CCD port multi speed guiding capabilities into the ‘506’ ala lx200/APM909
HW design and parts list complete but not posted yet.
Source code available for non-commercial use, click me
Update 5/13/2008
Snooping the Aux bus while the AS interacts with a 1244 focuser.
Update 5/12/2008
Note on PIC programmers: The JDM programmer and the 16F627/8 do not get along well together.
There is a sequence the various power and voltages need to be applied and the JDM cannot do it alone because of circuit limitations.
JDM programmer mod for 16F627/8 that works for me
Update 4/30/2008
Picture of clone 506 cable on protoboard.
PIC 16F628 left, crystal, MAX202 right
Below the crystal is an LM317T with Vout = 1.25*(1+R2/R1) R1 = 360 ohms and R2 =1k ohms, Vout = 4.72V (use a 78L05!)
Biggest pain is the modular 4 pin connector for the Aux Bus. It is a narrow version, I used a Dremel to trim down a 4 wire phone cable from the dollar store.
Current draw measured from Autostar = 25ma but may be up to ~40ma (parts tolerances)
Wires from Autostar
Black – ground from Autostar
Green – AuxClock
Red – AuxData
Yellow – Power
How to get the parts count down:
Buy a cheap cell phone to serial cable. I have one that has a max232 in the hood of the db9. Requires power from the clone board with 220 ohm resistor.
Use the internal 4Mhz oscillator of the PIC, baud rate may suffer up to 1% because of chip tolerances.
Still need to convert the Aux Bus power to around 5V, use a 78L05 voltage regulator.
Use a PIC 16F688, a 14 pin chip but not supported by the Hi-Tech Lite C free compiler , the 16F627 is code and pin compatible with the 16F628 I used.
Doing the above will get you down to one
chip, 3 resistors (/MCLR pullup, 1k’s to Aux Clk and Data), bypass caps and the
regulator. I’ll cobble this together in the next few weeks and post the
results. Total cost will be about the same (~$20) but footprint will be
drastically smaller.
Coding update: When the Autostar is in download mode it is –not- on a 130ms cycle but rather back to back cycles. Implications of this are for the ‘W’ command (write to Autostar), you should see 20-30CPS to the Autostar if sending 1 byte per cycle. I still do not know the number of bytes sent in every ‘W’ command from Autostar Updater so it –will- blow out the code as supplied at the link if you try it and MAY CAUSE harm to the Autostar if the ‘W’ command is used. The code at the link has an input of 0x11 being a command that allows you to vary the terminating sequence sent to the Autostar (defaults to 0x0). See the code and look for 0x11.
Update 4/26/2008
Sample source code:
Source code and major parts list - Click here
Advances on the code, sample screen shots from Autostar Updater.
No pulldowns now required, ack’ing all ‘poll’ messages with a null (0x0) keeps autostar coming back at 130ms idle poll intervals.
Schematic from 4/23 updated below.
‘Download mode’ writing (the ‘W’ command) not enabled on the PC interface, have not got the algorithm yet to make sure input buffer size does not exceed PIC memory and doing it a byte at a 130ms polling interval time would PAINFUL.
Update 4/23/2008
Basic schematic of 506 clone using PIC16F628
PIC RA3 is used to pull up/pull down Aux Data. To allow AS to start we need pull up, waiting for 5 seconds before checking Aux Clk.
When AS starts to poll we pull it down. If externally powered Aux Clk is monitored and if it goes away for 6 seconds we pull it up.
AS polls at 5 second interval if Aux Data not pulled down to a low float with the pull down it polls every 130ms and we can send to it at that interval.
Experiments with 2 Aux bus elements, namely this clone cable and a 1244 focuser are not promising so far the focuser may start running at any time when we write to the AS and at that time the AS may or may not lose capability to control the focuser.
And, by the way, the 1244 focuser Aux bus address is 0x01. The 506 cable is 0x11.
Source code coming!
Update 4/21/2008
Built a PIC based ‘506’ cable clone
Prototype:
PC RS232 (far left lower), MAXIM 202CPE(left), 20MHZ clock(middle), PIC 16F628(right)
Red is Aux Data, Yellow is Aux Clock
4.7k ‘pulldown’ on AuxData to get the AS to poll us every 130ms (versus every 5 seconds)
A lot of probe tap points on the PIC pins
Autostar 494 talking on Aux Bus
From left group to right large group is 130ms, the small groups in the middle are AS talking to the RA and DEC motors.
Top trace is Aux Clock, bottom trace is Aux Data. The second set of heavy lines from the bottom is the Aux Data line ‘floating’
RS232 capture of SMP telling AS 494 to
slew an etx70 base.
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:21 PM.08264 (+0.3750 seconds)
30
35 3A 35 35 2E 37 23 2B 30 37 DF 32 35 23
05:55.7#+07ß25#
Request:
4/21/2008 7:19:22 PM.61364 (+0.0313 seconds)
3A
53 72 20 30 35 3A 32 35 2E 36 23 3A 53 64 20
:Sr 05:25.6#:Sd
2B
30 36 DF 32 31 23
+06ß21#
Answer:
4/21/2008 7:19:22 PM.98864 (+0.3750 seconds)
31
31
11
Request:
4/21/2008 7:19:22 PM.08264 (+0.0156 seconds)
3A
4D 53 23
:MS#
Answer:
4/21/2008 7:19:23 PM.87964 (+0.7969 seconds)
30 0
Request:
4/21/2008 7:19:24 PM.45764 (+0.5781 seconds)
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:24 PM.03564 (+0.5781 seconds)
30
35 3A 34 39 2E 32 23 2B 30 39 DF 33 35 23
05:49.2#+09ß35#
Request:
4/21/2008 7:19:26 PM.45764 (+0.7344 seconds)
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:26 PM.84764 (+0.3906 seconds)
30
35 3A 33 37 2E 36 23 2B 30 37 DF 32 36 23
05:37.6#+07ß26#
Request:
4/21/2008 7:19:27 PM.95764 (+0.6094 seconds)
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:28 PM.37964 (+0.4219 seconds)
30
35 3A 33 33 2E 35 23 2B 30 35 DF 34 37 23
05:33.5#+05ß47#
Request:
4/21/2008 7:19:29 PM.45764 (+0.5469 seconds)
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:29 PM.78564 (+0.3281 seconds)
30
35 3A 32 37 2E 32 23 2B 30 36 DF 31 36 23
05:27.2#+06ß16#
Request:
4/21/2008 7:19:30 PM.95764 (+0.6406 seconds)
3A
47 52 23 3A 47 44 23
:GR#:GD#
Answer:
4/21/2008 7:19:31 PM.31664 (+0.3594 seconds)
30 35 3A 32 35 2E 37 23 2B 30 36 DF 32 30 23 05:25.7#+06ß20#