Forum Index
HomeZBasic Home   Forum RulesForum Rules   Forum FAQForum FAQ   MemberlistMemberlist   UsergroupsUsergroups   RSS FeedRSS Feed
Site SearchSite Search   LinksLinks   DownloadDownload   Digests and SubscriptionsDigests and Subscriptions
ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in   RegisterRegister
Serial Download / Monitor / Debug link to ZX-40 or ZX-xx

 
Post new topic   Reply to topic    Forum Index -> ZBasic Language
Author Message
zbasicandy



Joined: 26 Jan 2006
Posts: 193
Posted: 22 April 2006, 14:55 PM    Post subject: Serial Download / Monitor / Debug link to ZX-40 or ZX-xx Reply with quote
I need to know what is taking place in the way of communications between the PC and the ZX-xx when the serial download cable is connected.

Conditions: I have debug statements going to the PC for diagnostics.

Problem: Removing the serial cable causes a timing delay, I believe, which causes my program to work differently. Any comments?
Back to top
dkinzer
Site Admin


Joined: 03 Sep 2005
Posts: 2593
Location: Portland, OR
Posted: 22 April 2006, 15:45 PM    Post subject: Reply with quote
Code:
I need to know what is taking place in the way of communications between the PC and the ZX-xx when the serial download cable is connected.

There are two distinct phases: downloading and execution. During downloading, the PC sends records to the ZX which are acknowledged by sending a response back to the PC. During execution, there is no interaction at all unless your program initiates it.

When the serial cable is disconnected, the serial input lines (RxD and ATN) are not being driven. On the ZX-24, the ATN line has a pull down resistor that keeps the line from floating and inadvertently resetting the processor. The RxD line has no pull down resistor (on board revisions R0 through R2). Consequently, garbage characters may show up in the COM1 input queue.

You can add a pull down by connecting a 10K resistor between pin 2 of the ZX-24 and ground to see if that changes the behavior of your program.
Back to top
zbasicandy



Joined: 26 Jan 2006
Posts: 193
Posted: 23 April 2006, 1:44 AM    Post subject: Serial Monitor / Download / Debug communication problem Reply with quote
Quote:
You can add a pull down by connecting a 10K resistor between pin 2 of the ZX-24 and ground to see if that changes the behavior of your program.


I put a 10k "pullup" on the receive input on the ZX-40 (pin 14).
I also pulled it down with a 10K. In either case it seems to help a lot ...
further long term testing is needed.
Note: Pin 15 already had a heavy 6.8K pullup on the transmit output.
Back to top
dkinzer
Site Admin


Joined: 03 Sep 2005
Posts: 2593
Location: Portland, OR
Posted: 23 April 2006, 2:31 AM    Post subject: Reply with quote
Quote:
I put a 10k "pullup" on the receive input on the ZX-40 (pin 14).
I also pulled it down with a 10K.


The pulldown should be placed on the RS-232 side of the receiver. That will ensure that the ZX sees the idle state when the serial cable is disconnected.

Some RS-232 level converters already have pull downs on the RS-232 side and pull ups on the TTL side. If you are using one of these chips, check the datasheet.
Back to top
Display posts from previous:   
Post new topic   Reply to topic    Forum Index -> ZBasic Language Time synchro. with the server - Timezone/DST with your computer
Page 1 of 1

 


All content Copyright © 2005-2012 Elba Corp. All Rights Reserved.
Opinions expressed in posts are those of the author and not necessarily those of Elba Corp.
Powered by phpBB © 2001, 2005 phpBB Group