Shop OBEX P1 Docs P2 Docs Learn Events
DS1307 RTC and Supercap - SERIAL CONNECTIONS ??? — Parallax Forums

DS1307 RTC and Supercap - SERIAL CONNECTIONS ???

ArchiverArchiver Posts: 46,084
edited 2004-03-18 16:13 in General Discussion
--- In basicstamps@yahoogroups.com, "erniem1957" <ernie@c...> wrote:
> I'm attempting to add on a DS1307 RTC (real time clock) with a
> supercap power backup.
>
> Seems the cap isn't charging from the pin as I expected it would,
> that some other means of keeping the charge must be supplied.
>
> Does anyone know of an app note for doing this? Thanks.


Hi all,

I was thiking of how to best utilize a RTC.

In reading the data sheets, it seems that pins 1,2,3 and 4 of the BS2
are Tx, Rx, ATN and Gnd. Also listed as SOUT and SIN for 1 and 2.

Are there preferred pins to use ?

I'm thinking of the best way to add a clock and not use additonal
pins if I can get away with not having to.

Dave

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-03-18 15:13
    The 1302 (and I assume the 1307) utilize the
    SPI interface. The BS2 commands 'SHIFTIN' and
    'SHIFTOUT' support this interface. Typically,
    you need a Data line, and a Clock line, and
    also a ChipSelect line.

    You CAN get away with keeping the chip
    ALWAYS selected, if you then use the 'Clock'
    line to also 'select' the chip. Thus you need
    2 or 3 pins to talk to the 1307, using the
    SPI code. Check out the 1302.bs2 demo on
    the Files section of the Group site.


    --- In basicstamps@yahoogroups.com, "Dave Mucha" <davemucha@j...>
    wrote:
    > --- In basicstamps@yahoogroups.com, "erniem1957" <ernie@c...> wrote:
    > > I'm attempting to add on a DS1307 RTC (real time clock) with a
    > > supercap power backup.
    > >
    > > Seems the cap isn't charging from the pin as I expected it would,
    > > that some other means of keeping the charge must be supplied.
    > >
    > > Does anyone know of an app note for doing this? Thanks.
    >
    >
    > Hi all,
    >
    > I was thiking of how to best utilize a RTC.
    >
    > In reading the data sheets, it seems that pins 1,2,3 and 4 of the
    BS2
    > are Tx, Rx, ATN and Gnd. Also listed as SOUT and SIN for 1 and 2.
    >
    > Are there preferred pins to use ?
    >
    > I'm thinking of the best way to add a clock and not use additonal
    > pins if I can get away with not having to.
    >
    > Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-18 15:52
    --- In basicstamps@yahoogroups.com, "Allan Lane" <allan.lane@h...>
    wrote:
    > The 1302 (and I assume the 1307) utilize the
    > SPI interface. The BS2 commands 'SHIFTIN' and
    > 'SHIFTOUT' support this interface. Typically,
    > you need a Data line, and a Clock line, and
    > also a ChipSelect line.
    >
    > You CAN get away with keeping the chip
    > ALWAYS selected, if you then use the 'Clock'
    > line to also 'select' the chip. Thus you need
    > 2 or 3 pins to talk to the 1307, using the
    > SPI code. Check out the 1302.bs2 demo on
    > the Files section of the Group site.


    I guess I was hoping for method of using less pins, and maybe more
    dedicated pins for the serial comm.

    Dave







    >
    >
    > --- In basicstamps@yahoogroups.com, "Dave Mucha" <davemucha@j...>
    > wrote:
    > > --- In basicstamps@yahoogroups.com, "erniem1957" <ernie@c...>
    wrote:
    > > > I'm attempting to add on a DS1307 RTC (real time clock) with a
    > > > supercap power backup.
    > > >
    > > > Seems the cap isn't charging from the pin as I expected it
    would,
    > > > that some other means of keeping the charge must be supplied.
    > > >
    > > > Does anyone know of an app note for doing this? Thanks.
    > >
    > >
    > > Hi all,
    > >
    > > I was thiking of how to best utilize a RTC.
    > >
    > > In reading the data sheets, it seems that pins 1,2,3 and 4 of the
    > BS2
    > > are Tx, Rx, ATN and Gnd. Also listed as SOUT and SIN for 1 and 2.
    > >
    > > Are there preferred pins to use ?
    > >
    > > I'm thinking of the best way to add a clock and not use additonal
    > > pins if I can get away with not having to.
    > >
    > > Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-18 16:10
    You can only use SIN and SOUT for serial communication (SERIN and
    SEROUT) with an external device (these pins are the BASIC Stamp's
    programming port). When using them, you specify pin 16. These pins are
    also used by DEBUG and DEBUGIN, but are otherwise unavailable for
    general program use.

    If you use an I2C clock like the DS1307, you're only using two pins and
    these can be shared with other devices. One of my favorite devices is
    the MCP23016 IO expander from Microchip. For those of you that read
    Nuts & Volts, watch for my May column where I use the MCP23016 (costs a
    couple bucks) to make a very inexpensive LCD terminal.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=1IBp-XDjKy28fCyEnPHZVdob_1RygojTieGtchAp1x72fTrDjZeg8Q19fYgEQ3r6jKP3ixMDLtFbdvA]davemucha@j...[/url
    Sent: Thursday, March 18, 2004 8:49 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: DS1307 RTC and Supercap - SERIAL CONNECTIONS
    ???

    Hi all,

    I was thiking of how to best utilize a RTC.

    In reading the data sheets, it seems that pins 1,2,3 and 4 of the BS2
    are Tx, Rx, ATN and Gnd. Also listed as SOUT and SIN for 1 and 2.

    Are there preferred pins to use ?

    I'm thinking of the best way to add a clock and not use additonal
    pins if I can get away with not having to.

    Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-18 16:13
    The DS1302 uses SPI (3 wires), the DS1307 uses I2C (2 wires). To your
    point, you could keep the DS1302 selected all the time, but this would
    prevent sharing the line. I'd go with the DS1307 -- even for non
    BS2p/BS2pe BASIC Stamps. I2C is easy to bit-bang with the BS2, BS2e,
    and BS2sx.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Allan Lane [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hUhufK1uBMhbcbQerhiZzY7Nb3ou2ywIShLIAampah9JieBN3itIqxTURTTFAEgt8BC3tO3ZjDWB70r8SHGCoc39]allan.lane@h...[/url
    Sent: Thursday, March 18, 2004 9:14 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: DS1307 RTC and Supercap - SERIAL CONNECTIONS
    ???


    The 1302 (and I assume the 1307) utilize the
    SPI interface. The BS2 commands 'SHIFTIN' and
    'SHIFTOUT' support this interface. Typically,
    you need a Data line, and a Clock line, and
    also a ChipSelect line.

    You CAN get away with keeping the chip
    ALWAYS selected, if you then use the 'Clock'
    line to also 'select' the chip. Thus you need
    2 or 3 pins to talk to the 1307, using the
    SPI code. Check out the 1302.bs2 demo on
    the Files section of the Group site.


    --- In basicstamps@yahoogroups.com, "Dave Mucha" <davemucha@j...>
    wrote:
    > --- In basicstamps@yahoogroups.com, "erniem1957" <ernie@c...> wrote:
    > > I'm attempting to add on a DS1307 RTC (real time clock) with a
    > > supercap power backup.
    > >
    > > Seems the cap isn't charging from the pin as I expected it would,
    > > that some other means of keeping the charge must be supplied.
    > >
    > > Does anyone know of an app note for doing this? Thanks.
    >
    >
    > Hi all,
    >
    > I was thiking of how to best utilize a RTC.
    >
    > In reading the data sheets, it seems that pins 1,2,3 and 4 of the
    BS2
    > are Tx, Rx, ATN and Gnd. Also listed as SOUT and SIN for 1 and 2.
    >
    > Are there preferred pins to use ?
    >
    > I'm thinking of the best way to add a clock and not use additonal
    > pins if I can get away with not having to.
    >
    > Dave
Sign In or Register to comment.