Sending text to GLCD using BV4511 interface

[Scampy]

Over the past few days I've been in correspondence with Tabsoft trying to resolve this issue. I'm now at a total loss, and I think even Tabsoft is baffled as the issue just doesn't make sense.

The hardware:
Easypic5, solderless breadboard, Arduino UNO, DS1307, 24C256 EEPROM, 18F4580, BV4512 board, FTDI USB board.

Testing:
Serial port monitor, Hantek 20mhz scope

Basically running a simple code to scan the I2c buss and if any device is found to display it's address via the serial monitor. When using an identical script on the Arduino all three devices (DS1307, 24C256 and BV 4512 board is detected and their addresses displayed on the serial monitor. Running the equivalent code on the PIC it finds the DS1307 and 24C256 fine, but when the BV board is connected the PBO code detects a poor response on the buss and displays a "fault" message.

Using the scope the normal 9 pulses can be seen on both Arduino and PIC when just the two devices are running, but when testing with the PIC, both SDA and CLK lines are taken to GND when the BV board is connected.

Thinking that it may be something to do with the EasyPIC5 board the PIC was programmed and then moved to the breadboard next to the DS1307 and 24C256 chips. The same issue occurred so this eliminated the EasyPic5 board as being the cause. I've tried 10K, 5.6K, 4.7K, and 1K pull-ups on the i2c buss lines, but that makes no difference.

Anyone have any ideas of further things to try?

I would like to thank tabsoft for all his help. We've been corresponding via e-mail, often with me doing the practical testing, and reporting back with screen shots etc so we can try and resolve this. The only issue being that due to locations (he's in the US and I'm in the UK) it's often meant that I'm up until 3am most mornings and now I'm walking around like a zombie !!

[Sherbrook]

Hi Scampy
You say when testing with PIC, SDA and CLK lines are taken low when BV4611 is connected. According to the data sheet this will cause the BV4611 to start up in SERIAL mode. Have you set the PIC to pull SDA & CLK LOW or are they HIGH untill you connect the BV4611? Do you have the PIC start up with SDA & SCK as inputs untill the BV4611 starts up?
Surely SDA and SCK should idle HIGH.
Phil
By the way I'm in the UK

[Scampy]

Hi Phil,

the device I have is the older 4512, which is now obsolete and replaced by the 4611, which I've been told by Jim (the developer) is a "better" device. Tabsoft has managed to get the device responding to a poll from the PIC. It's complicated, but lest just say the Arduino and it's programming language sticks to the true correct protocol of the i2c standard, where as PBP appears to use an abbreviated version which mainstream devices can tolerate, but the BV4511 doesn't.

I'm also testing the GLCD as I may of damaged it when I connected it to the EasyPic5 board. On the EP5 the CS1 and CS2 are at one end of the header, but on the GLCD pins 15 and 16 are CS pins, so everything is then out by 2.... I need to do some further testing to make sure the GLCD works (going to fly wire to the correct pins one for one when the wires arrive). Once that has been checked and i can confirm it works then the fun begins in trying to get the BV4512 to receive and correctly interpret the PBP instructions to display text correctly....

If only someone manufactured an 8 x 20 LCD with built in character set based on the standard HD chipset... life would be a lot simpler... but then I guess PBP would only support LCD's up to 4 x 20.

I'm not going to post up the PBP code as Tabsoft is the main contributor, but I'm sure that once we have resolved this it will be put up for reference should some other poor soul happens to have one of these boards and wants to code in PBP

[Scampy]

Received a 128 x 64 GLCD with touch screen from MikroElektronica that works fine with the EasyPic5 demo - so I know it's working.

Breadboarded the BV controller to the GLCD carefully noting the pin mapping as the Mikro screen does not use the same pin outs as the board. It powers up, displayed the default message and I can turn off the screen and backlight by sending the appropriate code and value to the I2C address

 BVCmd = $6
opt=1

i2cwrite SDA,SCL, BVAddr ,BVcmd,opt

But trying to produce anything graphical like turning on pixels or drawing boxes fails so I tried my other piggyback board. It to powers up, displays it's demo screens. However reading the limited "manual" (http://www.digole.com//images/file/T...ter-Manual.pdf) it doesn't have the same type of command set, more for hyperterminal....

Would welcome suggestions as to how to configure this puppy to use it's internal fonts to give me the equivalent of an 8 x 20 LCD as I've not only gone grey with this, but now getting bald

[Scampy]

Ok I gave up with the BV4512 board and the I2C connectivity of the Digole board, and stested the Digole board in default serial mode.

It took a while but it works.

Having the built in selectable fonts makes this behave as if it was a large LCD - which for now is what I'm after.