Post by thread:[pic] interfacing PIC16F877 with AD7713(adc)

Hi, I am trying to interface an adc(AD7713 from Analog Devices, 24 bit resolution) with PIC16F877. The adc can communicate with microcontrollers using synchronous serial port communication (either SPI or using the Synchronous mode of the USART feature). I don't want to use the RX/TX pins of the 877 for interfacing with adc,as I want to use them to connect to a serial port of a PC. I am forced to use the SPI, but there is only one data line for the adc and I need 2 lines (for SDI and SDO) to use the SPI feature on 877. Is there anyway to use/apply "wired-or" kind of connection (available in the 68HC11 on the SPI ports) with the 877. Thanks in Advance, Sivaram -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

I don't believe you have to use both of the lines on the f877. If you read the mid-range ref manual, it gives an explanation for the SDO line. Then again, i'm not sure I fully understood your question, so I might not even be answering the right thing :-) Quoting Sivaram Cheekiralla <spam_OUTsivaramTakeThisOuTMIT.EDU>: {Quote hidden}> Hi, > I am trying to interface an adc(AD7713 from Analog Devices, 24 bit > resolution) with PIC16F877. The adc can communicate with microcontrollers > using synchronous serial port communication (either SPI or using the > Synchronous mode of the USART feature). I don't want to use the RX/TX pins > of the 877 for interfacing with adc,as I want to use them to connect to a > serial port of a PC. I am forced to use the SPI, but there is only one data > line for the adc and I need 2 lines (for SDI and SDO) to use the SPI feature > on 877. Is there anyway to use/apply "wired-or" kind of connection > (available in the 68HC11 on the SPI ports) with the 877. > > Thanks in Advance, > Sivaram > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > ---------------------------------------- This mail sent through http://www.mywaterloo.ca -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, In the manual for the adc, they have given examples (2) of interfacing with microcontrollers. One of them is 8XC51 and the otherone is 68HC11. The 8XC51 uses the Mode 0 for receiving/transmitting data to the adc, while the 68HC11 uses SPI. I am assuming that SPI is a "data excahnge" protocol and the process of communication would terminate if I disable the SDO. Can someone clarify the issue ? Thanks a lot, sivaram On Thu, 27 Feb 2003 .....jdharKILLspam@spam@engmail.uwaterloo.ca wrote: {Quote hidden}> I don't believe you have to use both of the lines on the f877. If you read the > mid-range ref manual, it gives an explanation for the SDO line. Then again, > i'm not sure I fully understood your question, so I might not even be > answering the right thing :-) > > Quoting Sivaram Cheekiralla <sivaramKILLspamMIT.EDU>: > > > Hi, > > I am trying to interface an adc(AD7713 from Analog Devices, 24 bit > > resolution) with PIC16F877. The adc can communicate with microcontrollers > > using synchronous serial port communication (either SPI or using the > > Synchronous mode of the USART feature). I don't want to use the RX/TX pins > > of the 877 for interfacing with adc,as I want to use them to connect to a > > serial port of a PC. I am forced to use the SPI, but there is only one data > > line for the adc and I need 2 lines (for SDI and SDO) to use the SPI feature > > on 877. Is there anyway to use/apply "wired-or" kind of connection > > (available in the 68HC11 on the SPI ports) with the 877. > > > > Thanks in Advance, > > Sivaram > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > > ---------------------------------------- > This mail sent through http://www.mywaterloo.ca > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

On Thursday 27 February 2003 03:04 pm, Sivaram Cheekiralla wrote: > In the manual for the adc, they have given examples (2) of > interfacing with microcontrollers. One of them is 8XC51 and the > otherone is 68HC11. The 8XC51 uses the Mode 0 for > receiving/transmitting data to the adc, while the 68HC11 uses SPI. > I am assuming that SPI is a "data excahnge" protocol and the > process of communication would terminate if I disable the SDO. Can > someone clarify the issue ? I've used similar A/D converters, and found that it was easy enough just to "bit bang" them. Dedicate 1 I/O line to the data line, 1 to the clock, plus however many additional ones you need. When writing to the chip, make your I/O line an output; when reading from it, make the I/O line an input. You may want to use a pull-up resistor. -- Ned Konz http://bike-nomad.com GPG key ID: BEEA7EFE -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics