AXE020 talking to a AXE033

C

charentemaster

New Member
Hi,
having trouble getting the 28X1 talking to the serial LCD, is the correct
program line '' serout 7". Since the programmed 'message' is not repeated
on the LCD screen. I have tried the 08M talking to the picaxe 'terminal'
window and this device uses ''serout 0'' and works a treat. In monitoring
the serin pin on the AXE033 with a scope no data appears when trying to
talk from the AXE020. Have also tried a longer initialise time eg pause 1000
but to no avail.:confused:
 
B

BeanieBots

Moderator
Obviously "serout 0" or "serout 7" depends on which output pin you have connected the AXE033 to, but I suspect that the real problem is that you are connecting the AXE033 to the darlington output and not directly to the PICAXE pin.

You can either remove the darlington array and replace it with a DIL resistor pack or connect to the holes directly behind the array rather than after the array.
 
C

charentemaster

New Member
axe020 >> axe033

no taking the 'output' from the 3 terminal molex connector.
Also the pen cells are giving 4.7v and current consumption around 3.6mA
after initial surge.
The LCD seems working since stand-alone on shorting the clk pins get the
00.00 clock display at contrast pot near limit:(
 
B

BeanieBots

Moderator
To use the AXE033 from the programming serial output pin you need to use "sertxd" not "serout".
Unfortunatley though, there is no command control over the baud rate which is fixed at 9600. To change that to 2400 you will need to underclock the PICAXE.
 
C

charentemaster

New Member
additional

Just re-tried with your suggestion and it works a treat.
Unplugged the darlington circuit and inserted the data wire into the DIL
socket on pin 28 or output 7 and hey presto!!!
thanks, however how many other people have been 'caught-out' perhaps
a word or two in the data sheet is in order.
 
hippy

hippy

Ex-Staff (retired)
Others have encountered the same issue and it has been noted.

Any presumption that users would know Darlingon Drivers and the ULN2803A are only capable of sinking current or they'd be using such boards in an environment, such as a classroom, where the electrical characteristics would be explained is obviously not as sound as it may have been thought.
 
D

Dippy

Moderator
Well, this fundamental issue has cropped up many, many times to my recollection over the last 5 years, so I'm very glad it's been noted at last. :rolleyes:

Gosh, I honestly don't mean to sound cheeky, but I would have thought the regularity of this confusion would have confirmed post#8 Para2 ages ago. (surely?? )

It would be really, really helpful and constructive if a few lines of text and a drawing or two were put into the rel. Data Sheets to clarify the Darlington chip issue.
Surely these minor extras wouldn't take longer to implement than a Westy coffee break? :)

It could save hours of Forum reply time and be really helpful to Customers especially the new ones.
 
C

charentemaster

New Member
reply to dippy

Yes in just reading the relevant data sheets it is not mentioned the fact
that the serout terminal on the 28X1 is in fact at 9600 bauds or that the
use of a darlington is not permitted.
Anyway I am glad that the circuits are working and increased my knowledge
base, but nopt in the best manner.
Tahnks all:rolleyes:
 
J

john2051

New Member
re:

Hi,
There is a small reference to not using the dartlington array on page 8 of the axe033 datasheet, but it could be overlooked. I think the axe033 is so good, I now own 14 of them!!!

regards John
 
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