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DrWhoF
Joined: 06 May 2005
Posts: 334
Helped: 12
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 10 Dec 2005 5:13 ds12887 problem |
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I am testing a circuit with RTC DS12887, 87C52, 74LS373 and DS12887 on a vero-board.
I can access registers of seconds, years and control: 0A, 0B and 0C, but I can't access registers of minutes, hours, days and months. It looks like this: seconds are counting from 00 to 59 but there is no count on minutes and so on.
I can write a number to and read form (00 to 99) the years register.
I tested DS12887 in another circuit and it is OK.
Why so weird behaviour and whay can be the reason?
Thanks.
DrWho
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IanP
Joined: 05 Oct 2004
Posts: 6492
Helped: 1542
Location: West Coast
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10 Dec 2005 8:02 ds12887 pic |
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Do uou have 2 of these DS12887? It doesn't make sense ..
And, what is the reason you have 74373?
The DS12877 has already built-in the multiplexed DATA/ADDRESS bus and all what you need to connect are the ALE, RD, WR and/or IRQ signals ..
Regards,
IanP
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DrWhoF
Joined: 06 May 2005
Posts: 334
Helped: 12
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13 Dec 2005 10:56 ds12887 |
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I have only one DS12887 and 27C512 as external program memory (74373 is used for this purpose).
The DS12877 is connected to AD bus with all control signals in place.
As I said I can read seconds and hours and I can access all controll registers and RAM locations.
Thanks.
DrWho
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IanP
Joined: 05 Oct 2004
Posts: 6492
Helped: 1542
Location: West Coast
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13 Dec 2005 11:52 how to use irq signal of ds12887 |
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If you say that the DS12887 itself is not faulty then most likely you have software bugs..
Double check the sections of code where you read year, month, .., and seconds, and where you display or send somewhere results .. or if you would like post them here for verification ..
Regards,
IanP
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DrWhoF
Joined: 06 May 2005
Posts: 334
Helped: 12
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14 Dec 2005 10:04 ds12887 circuit |
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This is the code which I use to read from DS12877:
| Code: |
; Reading DS12887
MOV R0, #0Ah
Wait: MOVX A, @R0
JB ACC.7, Wait
MOV R0, #00h
MOVX A, @R0
MOV MSec, A
MOV R0, #02h
MOVX A, @R0
MOV MMin, A
MOV R0, #04h
MOVX A, @R0
MOV MHour, A
MOV R0, #07h
MOVX A, @R0
MOV MDay, A
MOV R0, #08h
MOVX A, @R0
MOV MMonth, A
MOV R0, #09h
MOVX A, @R0
MOV MYear, A
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This is the code which I use to display Date and Time:
| Code: |
; Date and Time transmission.
Year: MOV A, MYear
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MYear
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV R6, #0Dh ; "-"
LCALL Send_R6
Month: MOV A, MMonth
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MMonth
ANL A, #0Fh
LCALL Send_R6
MOV R6, #0Dh ; "-"
LCALL Send_R6
Day: MOV A, MDay
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MDay
ANL A, #0Fh
LCALL Send_R6
Hour: MOV A, MHour
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MHour
ANL A, #0Fh
LCALL Send_R6
MOV R6, #0Ah ; ":"
LCALL Send_R6
Minute: MOV A, MMin
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MMin
ANL A, #0Fh
LCALL Send_R6
MOV R6, #0Ah ; ":"
LCALL Send_R6
Second: MOV A, MSec
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MSec
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
RET
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Thanks.
DrWho
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IanP
Joined: 05 Oct 2004
Posts: 6492
Helped: 1542
Location: West Coast
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14 Dec 2005 11:09 ds12887,microchip |
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The code for reading the RTC looks perfectly fine ..
However, in the other section (Month, Day, Hour and Minute) after:
ANL A, #0Fh (lower nibble)
you should load R6 with A and then send R6; so, for example, Month should look like this:
Month: MOV A, MMonth
SWAP A
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
MOV A, MMonth
ANL A, #0Fh
MOV R6, A
LCALL Send_R6
.. and I think there are your missing Months, Days, Hours and Minutes ..
Good Luck and Regards,
IanP
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DrWhoF
Joined: 06 May 2005
Posts: 334
Helped: 12
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15 Dec 2005 9:30 ds12887 code for pic |
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Wow, it is working.
Thank you very,very much.
DrWho
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vratislav
Joined: 22 Aug 2005
Posts: 6
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09 Feb 2006 2:52 reading ds12887 |
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| DrWhoF wrote: |
Wow, it is working.
Thank you very,very much.
DrWho |
can you send me your code for to try use a DS12887, i`m use microchip`s pic but not communicate with the device. sorry my english!!
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IanP
Joined: 05 Oct 2004
Posts: 6492
Helped: 1542
Location: West Coast
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09 Feb 2006 7:07 ds12877 |
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I don't think any code written for 8051 and DS12887 will be of any help to you ..
First of all, the DS12887 uses multiplexed 8-bit address-data bus, which is pretty normal for 8051 architecture, but "strange" for PICs ..
From PIC user point of view much better option is RTC with I2C interface, for example PCF8583 ( http://www.amresearch.com/datasheets/pcf8583.pdf ), or DS1337 ( http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3128 ) ..
Regrads,
IanP
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Google
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09 Feb 2006 7:07 Ads |
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sharang
Joined: 02 Jun 2009
Posts: 18
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07 Nov 2009 7:20 Problem with DS12887 |
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#include<reg51.h>
#include<absacc.h>
sbit RS=P1^2;
sbit RW=P1^3;
sbit E=P1^4;
void put(unsigned char ch,bit rs);
void delay(unsigned int t);
void init(void);
void main()
{
int i=0x00;
delay(500);
//P0=0xFF; //Input Port
init();
put('R',1);
put('T',1);
put('C',1);
put(0xC0,0);
delay(2);
XBYTE[10]=0x20;
XBYTE[11]=0x83;
XBYTE[11]=0x03;
XBYTE[0]=41;
//XBYTE[11]=0x03;
while(1)
{
put(0xC0,0);
for(i=0x00;i<0x0A;i++)
{
// XBYTE[0]++;
put((XBYTE[0]<<0x0F)+0x30,1);
delay(500);
put(0x94,0);
put((XBYTE[10]<<0x0F)+0x30,1);
}
/*if(XBYTE[0]>=0x39)
XBYTE[0]=0x30;
*/
}
}
void init(void)
{
put(0x3C,0); //Set interface length
put(0x01,0); //Clear the display
put(0x06,0); //Set cursor move direction
put(0x0E,0); //Enable display cursor
return;
}
void put(unsigned char ch,bit rs)
{
E=1;
RW=0;
P2=ch;
RS=rs;
delay(1);
E=0;
delay(1);
RW=1;
return;
}
void delay(unsigned int t)
{ unsigned int k,l;
for(l=0;l<t;l++)
for(k=0;k<900;k++);
return;
}
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