Hi, Correction: I used to think MODRR is read only. If fact it isn't, sorry. Edward ----- Original Message ----- From: "Andrew Lohmann" <> To: <> Sent: Tuesday, March 22, 2005 12:41 PM Subject: Re: [68HC12] SPI on MC9S12DP256B > > Thanks for both replies. I have the pull-up turned on but had not > discovered MODRR register. The point on the single extra clock pulse is > that it is needs to be at the beginning, so that 16 bit data is returned > correctly shifted in. The AD977, LTC1609, or ADS7809 converters are a > bit unusual as they need 17 clock pulses not 16 to read at the result. > > Andrew > Edward Karpicz wrote: > >> Hi, >> >> I'd look at how different are PIMs of E128 and DP256B. MODRR is read >> only, >> so I'd verify first if MODRR accepts the port mapping you want. Aren't >> you >> using default MODRR value? >> BTW is it faster to bidbang extra SCK pulse to ADS7809 rather than to >> perform 8bit SPI transfer? >> >> Edward >> >> ----- Original Message ----- >> From: "Andrew Lohmann" <> >> To: "68HC12 yahoogroups.com" <> >> Sent: Monday, March 21, 2005 6:35 PM >> Subject: [68HC12] SPI on MC9S12DP256B >> >> >> > >> > Hi, >> > >> > >> > I have been using the spi port on MC9S12E128 successfully for some >> > time. >> > I am now working on another target which uses MC9S12DP256B instead. >> > Unfortunately the spi does not work on this other target, which I have >> > two of. I have worked through the erratas for silicon revision 1K79X, >> > and have to dealt with erratas 548, 479, 429, but not 794. I note that >> > the E128 works fine with or without the errata work-arounds included, >> > as >> > you would expect. >> > >> > I use the spi in master mode for input only from an A to D converter. >> > This A/D ADS7809, requires one extra clock pulse, for each completed >> > conversion, and word read out which I generate by toggling the SCK pin >> > with the spi disabled. I then enable the spi, which appears to be >> > running but there is no clock on the sck line. It is as if the pim has >> > grabbed the SCK pin in the case of the MC9S12DP256B, but not in the >> > case >> > of the MC9S12E128. >> > >> > What do you think is the solution? >> > >> > -- >> > Andrew Lohmann AMIIE >> > Design Engineer >> > >> > zeta_alpha2002 wrote: >> > What do you think is the solution? >> >> SPI0 add a 10K pullup on SS* pin PS7. Same for the other SPIs if you >> are using them. >> >> SPI1 same at PH3 >> SPI2 same at PH7 >> >> >> --- In , Andrew Lohmann <andrew.lohmann@b...> >> wrote: >> > Hi, >> > >> > >> > I have been using the spi port on MC9S12E128 successfully for some >> time. >> > I am now working on another target which uses MC9S12DP256B instead. >> > Unfortunately the spi does not work on this other target, which I have >> > two of. I have worked through the erratas for silicon revision 1K79X, >> > and have to dealt with erratas 548, 479, 429, but not 794. I note that >> > the E128 works fine with or without the errata work-arounds >> included, as >> > you would expect. >> > >> > I use the spi in master mode for input only from an A to D converter. >> > This A/D ADS7809, requires one extra clock pulse, for each completed >> > conversion, and word read out which I generate by toggling the SCK pin >> > with the spi disabled. I then enable the spi, which appears to be >> > running but there is no clock on the sck line. It is as if the pim has >> > grabbed the SCK pin in the case of the MC9S12DP256B, but not in the >> case >> > of the MC9S12E128. >> > >> > What do you think is the solution? >> > >> > -- >> > Andrew Lohmann AMIIE >> > -----------------------------Disclaimer----------------------------- > > This communication contains information which is confidential and may also > be privileged. It is for the exclusive use of the addressee. If you are > not the addressee please note that any distribution, reproduction, > copying, publication or use of this communication or the information is > prohibited. If you have received this communication in error, please > contact us immediately and also delete the communication from your > computer. We accept no liability for any loss or damage suffered by any > person arising from use of this e-mail. > > -----------------------------Disclaimer----------------------------- > > > Yahoo! Groups Links > > |