MCB 900 Verification of Running Program

Hello all,

We're a team of engineers working towards operating an automotive security and operation system using an encoded bluetooth signal that are having some simple troubles getting our main components to work. Thus far work has been done (starting today) on interfacing the P89LPC932 on an Keil MCB900 v4 with an LCD. We obtained an LCD interface for our 40x2 LCD by going here:

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and modifying it a little bit to suit our purposes. Our main.c currently compiles (even though there are a few subroutines in the driver that are not used). All we're trying to do is write a string to an LCD right now. And I'm not sure if the program isn't working or I'm having hardware issues. Are there any particular jumper settings that need to be in place for the programming/execution phases. Our code can be found here:

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I just want to know what's going on and if I'm doing things right.

Thanks,

M. Ross Bluekeys Team

Reply to
bluekeysteam
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Hi ,

Lets label P89LPC932 = LPC932

a) 3volt micro with 5volt LCD LPC932 (CMOS logic) has Vdd betwen 2.4v and 3.6v AND most LCD's are 5volt CMOS Logic).

If the Vdd_LCD = 5volt and Vdd_LPC932 =3.3v the output of LPC932 is not enough to product a logic high on the LCD inputs.

If Vdd_LCD = 3.3v then there will be a problem as the LCD Glass is adjusted for 5v.

b) 5volt LCD test If you make

Vdd_LCD = 5V and Vss_LCD (GND) = )volt and V_LCD_contrast = )volt ..... then a strip of LCD Characters should be on ir [] same as character

0x0FF.

c) Also the LPC932 is a 2 clock cycle device - AND the "standard" 80c51's micro's are 12 clock cycles ==> Hence any delay loops need to be 6x longer to achieve the same delay time.

d) LPC932 GPIO is default INPUT (hi-Impedance output) NOT Quasi-Bidirectional like "standard" 80c51

All of these factors need to be taken in to account.

Joe

Reply to
Joe G (Home)

"Joe G (Home)" wrote: *** and top-posted. Fixed ***

This seems to have suffered from typos. Unchanged.

Seems like a useful GP summary and set of check points. However the top-posting seriously harms its utility.

Please do not top-post. Your answer belongs after (or intermixed with) the quoted material to which you reply, after snipping all irrelevant material. I fixed this one. See the following links:

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Reply to
CBFalconer

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