| ??? 08/27/05 23:36 Read: times |
#100199 - Memory-mapped LCD initialization Responding to: ???'s previous message |
Hal Albach said:
Everything appears to be working fine on my 8052.com SBC except for Memory mapped LCD. I set it up with the M0I command and the display seems to initialize, that is, completely blank but no cursor as in Direct mode. Using the LCD write test command leaves the LCD blank. I've been able to duplicate the symptoms you described, Hal. It turns out it was a software problem within SBCMON rather than a hardware problem. The problem was a bug in SBCMON that caused the 4-bit mode flag to not be cleared when SBCMON was configured to use the memory-mapped connection. This caused it to send a configuration command to the LCD that told it was in 4-bit mode when, in fact, it was in 8-bit mode (since it is always in 8-bit mode in memory-mapped mode). I fixed this bug and the symptoms you described and which I reproduced disappeared. You can "work-around" the problem in version 1.3.0 of SBCMON by executing the M1I command which tries to configure the LCD for 8-bit direct-connect mode. The SBC will hang (as it receives no response from the LCD). Press the "reset" button and then execute the M0I command to configure the LCD for memory-mapped mode. Since the 4-bit mode will have been cleared by the "M1I" command, the SBC will subsequently talk to the LCD in 8-bit mode as it should. Of course, I would recommend downloading version 1.3.1 of SBCMON which has been updated here. Download this to your SBC via ISP to replace the existing version. The problem should then be resolved. The reason I hadn't detected this bug earlier is because in testing I would connect the LCD in 4-bit direct-connect (mode 2), then 8-bit direct-connect (mode 1, which would clear the 4-bit flag), and then would move the LCD to the memory-mapped connector and execute the mode 0 initialization... but since the 4-bit flag had been cleared by the previous M1I instruction, I ran into no problems. Note that in version 1.3.1 of SBCMON I have also removed the "LF" from end-of-line sequences. This means you will have to configure your terminal program to "append LFs to CRs." I did this because SBCMON was not appending LFs to CRs in all conditions so I decided to just have it send CRs and let the terminal program add LFs if the user's environment requires them. Regards, Craig Steiner |
| Topic | Author | Date |
| 8052.com SBC | 01/01/70 00:00 | |
| SBC | 01/01/70 00:00 | |
| I'm Interested, but no big hurry | 01/01/70 00:00 | |
| Good point | 01/01/70 00:00 | |
| BTW | 01/01/70 00:00 | |
| I'll update | 01/01/70 00:00 | |
| This is a nice chip when you need pins g | 01/01/70 00:00 | |
| Questioins | 01/01/70 00:00 | |
| elaborations | 01/01/70 00:00 | |
| RD2 programming | 01/01/70 00:00 | |
| Question | 01/01/70 00:00 | |
| RD2 and PSEN | 01/01/70 00:00 | |
| LeDot | 01/01/70 00:00 | |
| solder point | 01/01/70 00:00 | |
| go figure | 01/01/70 00:00 | |
| solder point/LeDot | 01/01/70 00:00 | |
| Jumper/button | 01/01/70 00:00 | |
| datasheet | 01/01/70 00:00 | |
| RD2, /PSEN and the joy of being perfect | 01/01/70 00:00 | |
| I think | 01/01/70 00:00 | |
| Herr Ohm says no | 01/01/70 00:00 | |
| Hands off | 01/01/70 00:00 | |
| no touch | 01/01/70 00:00 | |
| tidbits | 01/01/70 00:00 | |
| AT89S8253 | 01/01/70 00:00 | |
| First hand experiance | 01/01/70 00:00 | |
| RE:Experience | 01/01/70 00:00 | |
| SBC page updated | 01/01/70 00:00 | |
| Required HW for 8052.com Institute of uC | 01/01/70 00:00 | |
| that Erik has voluteered to teach ??? | 01/01/70 00:00 | |
| Retirement | 01/01/70 00:00 | |
| Well | 01/01/70 00:00 | |
| genetically as well | 01/01/70 00:00 | |
| I too... | 01/01/70 00:00 | |
| u51 one possibility | 01/01/70 00:00 | |
| I like part of that | 01/01/70 00:00 | |
| not good | 01/01/70 00:00 | |
| I see your point - did you see mine? | 01/01/70 00:00 | |
| got better | 01/01/70 00:00 | |
| you did not | 01/01/70 00:00 | |
| Are you sure about your .29$ | 01/01/70 00:00 | |
| oops | 01/01/70 00:00 | |
| single nand gate?? | 01/01/70 00:00 | |
| Ok spelling it out | 01/01/70 00:00 | |
| And it supports DS89C4x0! | 01/01/70 00:00 | |
| Nice effort | 01/01/70 00:00 | |
| PCB layouts | 01/01/70 00:00 | |
| not even gerber? | 01/01/70 00:00 | |
| ExpressPCB | 01/01/70 00:00 | |
| Keil was | 01/01/70 00:00 | |
| If needs be | 01/01/70 00:00 | |
| 8052.com SBC available for ordering | 01/01/70 00:00 | |
| Selling like hotcakes? | 01/01/70 00:00 | |
| Not bad | 01/01/70 00:00 | |
| AT89S8253 | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| Errata | 01/01/70 00:00 | |
| AT89S8253 ISP | 01/01/70 00:00 | |
| Didn't look very hard | 01/01/70 00:00 | |
| I already tried | 01/01/70 00:00 | |
| 8052.com SBC and 8052Sim | 01/01/70 00:00 | |
| Sort of and yes | 01/01/70 00:00 | |
| Pinnacle52 | 01/01/70 00:00 | |
| Why? | 01/01/70 00:00 | |
| Touche' | 01/01/70 00:00 | |
| Hard to resist | 01/01/70 00:00 | |
| Dress | 01/01/70 00:00 | |
| re classes etc | 01/01/70 00:00 | |
| re classes etc - an example | 01/01/70 00:00 | |
| Question on BOM | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| New Items added to 8052.com SBC Page | 01/01/70 00:00 | |
| 74LS573? | 01/01/70 00:00 | |
| Correct | 01/01/70 00:00 | |
| reset | 01/01/70 00:00 | |
| Errata | 01/01/70 00:00 | |
| Mine has arrived . . . | 01/01/70 00:00 | |
| Wow | 01/01/70 00:00 | |
| A minor problem | 01/01/70 00:00 | |
| Caps for MAX232 | 01/01/70 00:00 | |
| Whole point.... | 01/01/70 00:00 | |
| MAX232 Caps | 01/01/70 00:00 | |
| Deflux | 01/01/70 00:00 | |
| Works like a charm! | 01/01/70 00:00 | |
| Never mind, got it figured out | 01/01/70 00:00 | |
| Glad you got it working | 01/01/70 00:00 | |
| SBC-BASIC | 01/01/70 00:00 | |
| See email | 01/01/70 00:00 | |
| yes I will... | 01/01/70 00:00 | |
| Any luck with that yet? | 01/01/70 00:00 | |
| Not yet | 01/01/70 00:00 | |
| Sure! | 01/01/70 00:00 | |
| in that case... | 01/01/70 00:00 | |
| I've got a couple of RD2's | 01/01/70 00:00 | |
| http://www.efton.sk | 01/01/70 00:00 | |
| What about ED2's | 01/01/70 00:00 | |
| yes | 01/01/70 00:00 | |
| Basic 52/RD2 | 01/01/70 00:00 | |
| b52rd2 | 01/01/70 00:00 | |
| it works for me | 01/01/70 00:00 | |
| Real hackers | 01/01/70 00:00 | |
Basic 52 | 01/01/70 00:00 | |
| I got mine today! | 01/01/70 00:00 | |
| Darn the luck | 01/01/70 00:00 | |
| Comments | 01/01/70 00:00 | |
| Our Radio Shack Stinks | 01/01/70 00:00 | |
| An Idea | 01/01/70 00:00 | |
| 125 | 01/01/70 00:00 | |
| RE: '125 and JP4 | 01/01/70 00:00 | |
| Yes position? | 01/01/70 00:00 | |
| Got it - Bad 8253 | 01/01/70 00:00 | |
| No explanation | 01/01/70 00:00 | |
| You were right the first time - my bad | 01/01/70 00:00 | |
| No problem | 01/01/70 00:00 | |
| Memory mapped LCD problems | 01/01/70 00:00 | |
| Hmmm | 01/01/70 00:00 | |
| Building one | 01/01/70 00:00 | |
| Microseconds? | 01/01/70 00:00 | |
| Scale error | 01/01/70 00:00 | |
| Memory-mapped LCD initialization | 01/01/70 00:00 | |
| Thanks, Craig! It works! | 01/01/70 00:00 | |
| SBC - Manual | 01/01/70 00:00 | |
| SBC document | 01/01/70 00:00 |