Digital Alarm Clock in C

Rickey.

I have some good news and some not so good news; I have found out that the LCD is not fried and does work just fine, also that the program included in the HEX file is functioning because I am able to hear the buzzer go on/off and can be set with the switches. The downside I found out is that on my 8951 there are apparently predefined pins for each function, so what I was able to figure out is how to match the corrected pins up to the LCD.

I took your advice and created a simple display code and ran it, I think you’ll like the outcome , and found that the pin corrections worked. Now my question to you is in the HEX file can I reset the LCD pin connections to the following changes:

 

LCD	8051
Vss	Vee
VDD	VCC
VD	Ground
RS	P0.0
R/W	P0.1
E	P0.2
DB4	P0.4
DB5	P0.5
DB6	P0.6
DB7	P0.7

-JoshG

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Yes it is possible to do that.. but! its hard!
you need to change the opcodes wherever LCD is using P2
change it to P0. thats why i said.. hard
as the program is in C so.. that makes it more hard why don't you use P2?

And also you have to change the D7 from P2.7 to P0.7 lot of changes.. and hard to find in big hex file..

Ok so how about if I were to rewire it so that if follows this pattern to try to follow the existing code in the HEX file?

 

LCD	8051	P2
Vss	Vee	Same
VDD	VCC	Same
VD	Ground	Same
RS	P0.0	P3.7
R/W	P0.1	P3.6
E	P0.2	P3.5
DB4	P0.4	P2.4
DB5	P0.5	P2.5
DB6	P0.6	P2.6
DB7	P0.7	P2.7

-JoshG

I told you this way or that way! its the same. Its as hard as the previous one.
you need to interchange the address where the data is suppose to move.. i mean!
like 0xA0(P2) to 0x80(P1) as you wanted. but the thing is what if 0x80 comes in data so you gonna ruin the program.. and moreover if you are directly editing the .hex file then you need to calculate the checksum of each line and then put a new one. its a tough job. but its easy if you edit in a buffer or uploader program.

Still i wont recommend you do this rest is your wish!

your previous idea of changing P2 to P0 is much simpler than the one you just gave

Well ok if it is that complicated then I'll just try and stick with your original pin assignments; however could you tell me if I’m going in the right direction for these pin assignments and if possible where would I be able to attach Pin 4 on my LCD?

 

 

-JoshG

Sorry about the format issues above

In a text document put in a zip because .rtf not allowed

Please dont use your configuration. I am controlling RS and RW pins of LCD with P3.7 and P3.6 there is no different pin for reading and writing.
Do not confuse yourself. Simply follow the schematic as described. and make the connections. It will work.
You cannot use your configuration, because you cannot edit the hex file!! Hope you understood..

Oh ok that was where I was confused because when I was reading my 8951 manual and looking at P3.6 and P3.7 their used for External data memory write/read strobe so I figured that since apparently on my LCD the write/read functions were just on pin 5 that both pins on the 8951 must be tied together I’ll change my circuit as shown in the attached ZIP

-JoshG

Please don't take me wrong.. I am little short tempered
so.. please accept this.. you don't know what you are talking about..
Do you really know about LCD?
Please consult a book and study LCD properly.

i tell you about LCD in brief
----------------------------------
LCD has three portion of hardware connectivity
First:
Power and Contrast
Second:
Control Pins
Third:
Data Pins

Power and Contrast Pins: For powering the LCD and changing contrast. Contrast pin sometimes work with -ve voltage for some of the LCDs.

Data Pins: For sending Data to the LCD. The seventh data pin of LCD i.e. D7 is used as busy flag for checking the status of LCD.

Control Pins: There are three control pins in an LCD.
a) Register Select (RS)
b) Read/Write (RW)
c) Enable (EN)

a) RS: the pin RS is used to select register. either data or command register.
if RS = 1 » Data Register
RS = 0 » Command Register
b) RW: This pin is used for selecting the operation of LCD, either read/write.
if RW = 0 » Write
RW = 1 » Read
c) EN: To enable the LCD. usually a high means enable.

-----------------------------
So now we conclude that.. there is only one pin needed for RW and one pin for RS.. not two pins.. i hope you understood.

Don’t worry about it I’m not the best tempered individual myself I’m just trying to figure this out but this is the first time I’ve added an LCD display myself I usually use a driver board and not my 8051. So getting back I have re-read my LCD and 8051 manual trying to best match the pins up and I believe I have finally got the correct configuration:

 

 

 

**When interface is 4bits long Data is on DB4-DB7

*When interface is 8bits long Data is on DB0-DB7

 

What do you think?

 

-JoshG