ZXPand+ ZXPAND "OPE SER 19200" issues

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tdg8934
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ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sat Aug 05, 2017 6:45 pm

Charlie,

I used a meter and found +5v, Gnd on the ZXPand+ idc10 cable. I'm using a Parallax 2x16 Serial LCD with it having 4 modes (test, 2400, 9600, 19200).The LCD has pins for 5vdc, God and RX. I connected the i'dc 10 connectors pin 9 TX to the LCD RX as well as 5vdc and gnd pins.

When the LCD is set to 19200 via the mode switch on the LCD, I see some characters like GV on the top row and v5 or something on the second row upon power up of ZXPand+ with LCD attached. At 2400 and 9600 settings the LCD screen is blank like I would expect. I'm receiving another Parallax 4x20 serial LCD in the mail today which should operate identically.
How do I send a HIGH out from the ZXPand+ TX ?

tdg8934
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sat Aug 05, 2017 8:11 pm

I'm having a little success in seeing characters but at the wrong position. I have to send +5vdc (or a HIGH) command to the ZXPand+ Serial TX pin to initialize the LCD RX pin. Then I have to send the LCD Hex commands (or decimal 0-255) to tell the LCD where the cursor should be, turn LCD backlight off/on, etc.

Is there anyway to send the ZXPand+ serial TX pin Hex or Decimal commands besides text characters?

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Andy Rea
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by Andy Rea » Sat Aug 05, 2017 8:53 pm

i was under the impression you could put arbitrary bytes in memory somewhere ( say a rem statement ) and issue the connamd

ZXPAND "PUT SER *16514 32"

which would send 32 bytes stored in a line 1 rem statment...

least thats how i understand it..

regards Andy

p.s just a thought for SirMorris what about... PUT HEX 001122334455...
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

tdg8934
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sat Aug 05, 2017 9:31 pm

Thanks Andy. I will try that. Not at home at the moment. Bytes in decimal is fine so hex is nice but let's see if decimal works first.

tdg8934
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sun Aug 06, 2017 1:58 am

27979-Parallax-Serial-LCDs-Product-Guide-v3.1.pdf
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All,

I finally got it working meaning interfacing a Parallax Serial LCD to ZXPand+ on the serial port (IDC 10).

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This is showing a 2x16 Parallax LCD display.

I also have a bigger Parallax 4x20 LCD display that arrived today and the code works the same.

Tim
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Andy Rea
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by Andy Rea » Sun Aug 06, 2017 2:03 am

Great stuff, glad you got it working,

Regards andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

tdg8934
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sun Aug 06, 2017 12:09 pm

The only significant issue is that there needs to be a way to send 5vdc (High) and Gnd (Low) to the TX pin to initialize the LCD. The only work around so far is to run the program twice,

sirmorris
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by sirmorris » Sun Aug 06, 2017 4:12 pm

Looking good! I've been AFK until now and loads seems to have happened in the time being :D

Is there a time constraint on the high/low protocol for initialising the interface? Would sending a value with one bit set do the trick? like 00000010 binary.

tdg8934
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Re: ZXPand+ ZXPAND "OPE SER 19200" issues

Post by tdg8934 » Sun Aug 06, 2017 4:29 pm

There is no time constraint but trying to have something interesting for the vintage computer show next month. I will start focusing on the Atari joystick port testing next to understand how it works with ZXPand+ and then incorporate both joystick and LCD into a text demo.

It appears there is about 4.8vdc on TX when ZXPand is first turned on but it causes some strange characters and tones (LCD has a piezospeaker fir music notes). I would think this should cause it to initialize but there is something I'm missing or not understanding.

I tried using ZXPAND "OPE SER *16514 1". Where the REM Statement had a value for 255 for a HIGH but no go.

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