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Forum Index : Microcontroller and PC projects : mono maximite RTC
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BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Hi all. I am trying to fit an RTC to a monochrome Maximite. However, I don't know where to connect to SDA and SCL signals. I'm hoping to find them on the I/O socket, but which? Regards, Bob Devries Dalby, QLD, Australia |
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Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9030 |
Hi. I'm not sure if the original B/W Maximite supports I2C. I know that the first one I came across did not support serial either. I believe that Geoff added it(serial) later as a bit-banged option. Can't remember if the likes of I2C and SPI were added later or not. I have a feeling that the B/W Maximite IO pins were simply digital in, out, or some analog ones, but other then that.... Attached is the Maximite ZIP file including the manual and I/O pinout etc from Geoff's site(via the archive). Maximite_MMBasic_V2.2.zip EDIT: I am totally wrong. This is V4.4 of the firmware, manuals etc, and I2C is indeed supported. Open MMBasic manual PDF inside the zip, see Appendix B - I2C communications..... Maximite_MMBasic_V4.4B.zip Edited 2020-05-25 11:00 by Grogster Smoke makes things work. When the smoke gets out, it stops! |
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Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1584 |
The latest manual for the Mono Maximite is available here. On page 14 of the manual it shows how to connect a I2C RTC. Bill Keep safe. Live long and prosper. |
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flasherror Senior Member Joined: 07/01/2019 Location: United StatesPosts: 158 |
As someone who is using Olimex's Duinomite Mega with v4.5 firmware (should be same as Maximite Mono) here are some notes on RTC: 1. RTC must be PCF8563 - search ebay for some cheap RTC modules. Connect using I2C pins and power using 3.3v. (I believe the I2C pins are only 3.3v tolerant, so you want to power from 3.3v and not 5v even though the RTC module can work on either voltage. If this is not correct someone please correct me) Don't forget to install a battery! (Many RTC modules use CR1220) Mono maximite can only use PCF8563, although I believe micromites can use other RTC chips. 2. On first power-on after you have connected the RTC You need to set the RTC date/time using the RTC SETTIME command – this should be done once to set the RTC. RTC SETTIME YY,MM,DD,HH,MM,SS YY = last 2 year digits MM = month number (prefix with 0 if less than 10) DD = Day of Month (prefix with 0 if less than 10) HH = Time Hour (24 hour format 00-23) MM = Time Minute (00-59) SS = Time Seconds (00-59) 3. An important thing to remember is that even though the RTC is connected, MMBasic does not automatically update the time and date variables on power-on - your program must do RTC GETTIME on program start to read RTC and set MMBasic time$ and date$ variables. 4. Similarity, Setting Date$ and Time$ alone will not set RTC time! (Use RTC SETTIME to set RTC clock) 5. If RTC is not connected, the use of RTC commands will abort to basic prompt with "Error: PCF8563 not responding" error. This is not trappable (as far as I know) and represents a potential point of failure for an unattended program if the RTC was not connected or malfunctioning (would be nice if it returned a error code instead of aborting!) Hope this is helpful. Can someone please add this to fruitoftheshed, might be useful for others in the future. Edited 2020-05-27 12:44 by flasherror |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 5867 |
You can always query the RTC in Basic and check for errors before issuing the RTC commands. i2caddr = &h51 ' PCF8563 I2C address I2CEN 100,100 ' Enable I2C I2CRCV i2caddr, 0, 7, RTCbuff(0),1,2 I2CDIS print "0=ok 1=nack 2=timeout "; MM.I2C The code is 9 years old but worked well at the time. Jim VK7JH MMedit  MMBasic Help |
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