#garfield Logs

Apr 20 2021

12:25 AM rue_mohr: starting to wonder if a ram check would be a good idea
01:13 AM rue_mohr: I think I'm locking up the display
01:13 AM rue_mohr: I need a startup beep
01:19 AM rue_mohr: huh, soemthing about me telling the screen to move the cursor screws it all up
01:25 AM rue_mohr: oh I know, the screen goes into infinite busy
07:30 AM Tom_itx is now known as Tom_L
09:01 AM rue_mohr: polprog, do they sell securrity bit sets where you are?
09:03 AM polprog: im sure they do
09:03 AM polprog: i just dont have a set
09:13 AM rue_mohr: so, the cursor position code locks up the z80
09:13 AM rue_mohr: in a way that it cant even reset
09:13 AM rue_mohr: like, hard reset doesn't work
09:16 AM rue_mohr: I think its a problem with the z80 somehow
09:16 AM rue_mohr: I'll try changing it out
09:17 AM rue_mohr: oh wait, or the lcd is locking up and not clearing the busy flag
09:17 AM rue_mohr: hmmmm
09:27 AM aandrew: rue_mohr: how on earth do you lock up the MPU so hard that a reset won't clear it?
09:27 AM aandrew: sounds like the reset doesn't clear *everything* - perhaps some I/O or decoder needs to also get reset
09:28 AM rue_mohr: i DID TRY POWER CYCLING THE SCREEN, SO ITS NOT LIKE ITS WAITING FOR (sorry coding in caps) for that
09:28 AM aandrew: maybe reset the LCD controller as well when the reset button is pressed
09:28 AM rue_mohr: I dont think the lcd has a hard reset line
09:28 AM rue_mohr: but it has to be the lcd, right?
09:29 AM rue_mohr: I finished the program with a halt, and the halt light came on
09:29 AM rue_mohr: when I hit reset the halt light goes out
09:29 AM rue_mohr: but nothing
09:29 AM rue_mohr: a startup beep would be nice too
09:31 AM rue_mohr: I was wondering if it was setting the lcd to the CG write mode
09:31 AM rue_mohr: but I checked, its good
09:31 AM rue_mohr: I just write the new cursor address
09:38 AM rue_mohr: OMG
09:38 AM rue_mohr: first google hit
09:39 AM rue_mohr: "
09:39 AM rue_mohr: Busy flag never resets after "Set DDRAM address""
09:43 AM aandrew: oh>
09:43 AM aandrew: ?
09:43 AM rue_mohr: sounds like a chip bug
09:43 AM aandrew: that first hit I get from that is microchip.com
09:43 AM rue_mohr: but my code sets the cursor position in other places, and it works fine
09:44 AM rue_mohr: so there must be more to it
09:44 AM aandrew: well, just reset the LCD controller when you use the reset button
09:44 AM rue_mohr: I do not think there is hardware reset line
09:45 AM rue_mohr: no, the chip doesn't even have one
09:45 AM aandrew: sounds like time for a monostable "yup" to give a 300ms pulse to reset power
09:45 AM rue_mohr: I tried power cycling the screen tho
09:45 AM rue_mohr: maybe I didn't give it long enough
09:46 AM rue_mohr: a few times I was able to hold reset for like 8 seconds and have it come back
09:46 AM rue_mohr: which REALLY had me scratching my head
09:46 AM rue_mohr: this is a deeper bug I need to check details on
09:47 AM rue_mohr: I wonder if I send a command right after cursor position without checking the busy if its all good
09:48 AM aandrew: a BSS138 *after* any capacitor might help, but you have to also make sure none of the signal lines is high or that will back-power the display through the ESD diodes
09:48 AM rue_mohr: CALL SCRNBUSYLOOP
09:48 AM rue_mohr: SET 7,E ; SET POSIION (00 OR 40)
09:48 AM rue_mohr: OUT (C),E
09:48 AM rue_mohr:
09:48 AM rue_mohr: CALL SCRNBUSYLOOP
09:48 AM rue_mohr: my existing code does that with no issues
09:49 AM rue_mohr: I outright unplugged it for a like 5 seconds
09:49 AM rue_mohr: I'm wondering if invalid positions lock it up
09:49 AM rue_mohr: have to go to work tho
09:52 AM aandrew: unplugged it for 8s as in removed the module from the board?
09:52 AM aandrew: are there bypass caps on the module?
09:55 AM rue_shop1: no that big
09:56 AM aandrew: interesting issue.
01:08 PM aandrew: rue_mohr: you've probably seen this already, but fpga based graphics card for 8-bitter https://www.eevblog.com/forum/fpga/fpga-vga-controller-for-8-bit-computer/?topicseen
08:02 PM rue_mohr: lets see what they did...
08:05 PM rue_mohr: not seeing anything yet
08:06 PM rue_mohr: dont know what it is tho, no info
08:45 PM rue_mohr: give me a valid us zip code!
08:45 PM rue_mohr: 90210 isn't working
08:49 PM rue_mohr: drat this isn't working
09:01 PM aandrew: 15112
09:01 PM aandrew: pittsburgh
09:04 PM rue_mohr: the app for creating a samgsung account on the old samsung phone I have is too old
09:04 PM rue_mohr: I was able to do it online
09:04 PM rue_mohr: I need it to update the phone kernel
09:04 PM rue_mohr: its a demo phone
09:16 PM aandrew: hm?
09:16 PM aandrew: what're you up to?
10:22 PM rue_mohr: installed water sprayer system in greenhouse
10:23 PM rue_mohr: its just on a wind up timer for now
10:23 PM rue_mohr: watered other stuff thats dying in the tease-summer