Looking for simple way to interface BCD to serial (RS232)
in [Design]
|
From: Joerg on 27 Dec 2009 21:29 RFI-EMI-GUY wrote: > don wrote: >> RFI-EMI-GUY wrote: >>> I have a device that has a three digit LED display. The chip that >>> drives the LED also has four Binary Weighted outputs (1,2,4,8) and >>> three address pins for 100's, 10's and units. I want to drive a FIFO >>> UART of some sort to output an RS232 stream so that this device can >>> update a software program. Baud rate 300 to 4800 range would be nice >>> if possible. >>> >>> The updates are about 300/second >>> >>> Is there a real simple hardware FIFO UART that can do this without a >>> lot of extra hardware. I don't want a software fix unless I can do it >>> in PicAxe and can find code written. >>> >>> Off the shelf products OK I don't want to reinvent the wheel. >>> >> Do you docs on the outputs ? >> >> don > > > I think you are asking the specs of the driving chip? Its an ICM7217IJI > Common Cathode 4 LED Display/Programmable Up/Down Counter. The BCD I/O > pins and the segment drivers b, d and f (d1, d2, d3) used to select > 100's. 10's and units (I may have order reversed). > That will not be so trivial because this is a chip that drives the LED in muxed fashion. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Martin Riddle on 27 Dec 2009 22:23 "Joerg" <invalid(a)invalid.invalid> wrote in message news:7pqjftFe4cU2(a)mid.individual.net... > RFI-EMI-GUY wrote: >> don wrote: >>> RFI-EMI-GUY wrote: >>>> I have a device that has a three digit LED display. The chip that >>>> drives the LED also has four Binary Weighted outputs (1,2,4,8) and >>>> three address pins for 100's, 10's and units. I want to drive a >>>> FIFO UART of some sort to output an RS232 stream so that this >>>> device can update a software program. Baud rate 300 to 4800 range >>>> would be nice if possible. >>>> >>>> The updates are about 300/second >>>> >>>> Is there a real simple hardware FIFO UART that can do this without >>>> a lot of extra hardware. I don't want a software fix unless I can >>>> do it in PicAxe and can find code written. >>>> >>>> Off the shelf products OK I don't want to reinvent the wheel. >>>> >>> Do you docs on the outputs ? >>> >>> don >> >> >> I think you are asking the specs of the driving chip? Its an >> ICM7217IJI Common Cathode 4 LED Display/Programmable Up/Down Counter. >> The BCD I/O pins and the segment drivers b, d and f (d1, d2, d3) used >> to select 100's. 10's and units (I may have order reversed). >> > > That will not be so trivial because this is a chip that drives the LED > in muxed fashion. > There are separate BCD outputs, in addition to the LED drivers abcdefg. So he could use the muxs to latch the bcd data into shift registers. After 16 bits are latched, clock them out with start and stop bits. Cheers
From: don on 27 Dec 2009 22:38 Martin Riddle wrote: > "Joerg" <invalid(a)invalid.invalid> wrote in message > news:7pqjftFe4cU2(a)mid.individual.net... >> RFI-EMI-GUY wrote: >>> don wrote: >>>> RFI-EMI-GUY wrote: >>>>> I have a device that has a three digit LED display. The chip that >>>>> drives the LED also has four Binary Weighted outputs (1,2,4,8) and >>>>> three address pins for 100's, 10's and units. I want to drive a >>>>> FIFO UART of some sort to output an RS232 stream so that this >>>>> device can update a software program. Baud rate 300 to 4800 range >>>>> would be nice if possible. >>>>> >>>>> The updates are about 300/second >>>>> >>>>> Is there a real simple hardware FIFO UART that can do this without >>>>> a lot of extra hardware. I don't want a software fix unless I can >>>>> do it in PicAxe and can find code written. >>>>> >>>>> Off the shelf products OK I don't want to reinvent the wheel. >>>>> >>>> Do you docs on the outputs ? >>>> >>>> don >>> >>> I think you are asking the specs of the driving chip? Its an >>> ICM7217IJI Common Cathode 4 LED Display/Programmable Up/Down Counter. >>> The BCD I/O pins and the segment drivers b, d and f (d1, d2, d3) used >>> to select 100's. 10's and units (I may have order reversed). >>> >> That will not be so trivial because this is a chip that drives the LED >> in muxed fashion. >> > > There are separate BCD outputs, in addition to the LED drivers abcdefg. > So he could use the muxs to latch the bcd data into shift registers. > After 16 bits are latched, clock them out with start and stop bits. > > Cheers > > > > This is what I was wondering about. So my answer is "use a PIC". As long as there is a way to sync with the first digit, that with would be easy. don
From: Martin Riddle on 27 Dec 2009 23:19 <don> wrote in message news:Kq-dnfM2ZeS7taXWnZ2dnUVZ_rdi4p2d(a)forethought.net... > Martin Riddle wrote: >> "Joerg" <invalid(a)invalid.invalid> wrote in message >> news:7pqjftFe4cU2(a)mid.individual.net... >>> RFI-EMI-GUY wrote: >>>> don wrote: >>>>> RFI-EMI-GUY wrote: >>>>>> I have a device that has a three digit LED display. The chip that >>>>>> drives the LED also has four Binary Weighted outputs (1,2,4,8) >>>>>> and three address pins for 100's, 10's and units. I want to drive >>>>>> a FIFO UART of some sort to output an RS232 stream so that this >>>>>> device can update a software program. Baud rate 300 to 4800 range >>>>>> would be nice if possible. >>>>>> >>>>>> The updates are about 300/second >>>>>> >>>>>> Is there a real simple hardware FIFO UART that can do this >>>>>> without a lot of extra hardware. I don't want a software fix >>>>>> unless I can do it in PicAxe and can find code written. >>>>>> >>>>>> Off the shelf products OK I don't want to reinvent the wheel. >>>>>> >>>>> Do you docs on the outputs ? >>>>> >>>>> don >>>> >>>> I think you are asking the specs of the driving chip? Its an >>>> ICM7217IJI Common Cathode 4 LED Display/Programmable Up/Down >>>> Counter. The BCD I/O pins and the segment drivers b, d and f (d1, >>>> d2, d3) used to select 100's. 10's and units (I may have order >>>> reversed). >>>> >>> That will not be so trivial because this is a chip that drives the >>> LED in muxed fashion. >>> >> >> There are separate BCD outputs, in addition to the LED drivers >> abcdefg. >> So he could use the muxs to latch the bcd data into shift registers. >> After 16 bits are latched, clock them out with start and stop bits. >> >> Cheers >> >> > This is what I was wondering about. > > So my answer is "use a PIC". > > As long as there is a way to sync with the first digit, that with > would be easy. > > don Datasheet <http://www.intersil.com/data/fn/fn3167.pdf> Sync the digits with the Mux outputs. Cheers
From: Jan Panteltje on 28 Dec 2009 07:01
On a sunny day (Sun, 27 Dec 2009 22:23:06 -0500) it happened "Martin Riddle" <martin_rid(a)verizon.net> wrote in <hh98b5$c9l$1(a)news.eternal-september.org>: > > >"Joerg" <invalid(a)invalid.invalid> wrote in message >news:7pqjftFe4cU2(a)mid.individual.net... >> RFI-EMI-GUY wrote: >>> don wrote: >>>> RFI-EMI-GUY wrote: >>>>> I have a device that has a three digit LED display. The chip that >>>>> drives the LED also has four Binary Weighted outputs (1,2,4,8) and >>>>> three address pins for 100's, 10's and units. I want to drive a >>>>> FIFO UART of some sort to output an RS232 stream so that this >>>>> device can update a software program. Baud rate 300 to 4800 range >>>>> would be nice if possible. >>>>> >>>>> The updates are about 300/second >>>>> >>>>> Is there a real simple hardware FIFO UART that can do this without >>>>> a lot of extra hardware. I don't want a software fix unless I can >>>>> do it in PicAxe and can find code written. >>>>> >>>>> Off the shelf products OK I don't want to reinvent the wheel. >>>>> >>>> Do you docs on the outputs ? >>>> >>>> don >>> >>> >>> I think you are asking the specs of the driving chip? Its an >>> ICM7217IJI Common Cathode 4 LED Display/Programmable Up/Down Counter. >>> The BCD I/O pins and the segment drivers b, d and f (d1, d2, d3) used >>> to select 100's. 10's and units (I may have order reversed). >>> >> >> That will not be so trivial because this is a chip that drives the LED >> in muxed fashion. >> > >There are separate BCD outputs, in addition to the LED drivers abcdefg. >So he could use the muxs to latch the bcd data into shift registers. >After 16 bits are latched, clock them out with start and stop bits. > >Cheers Replace the whole chip by a PIC with a RS232 output. |