Microchip may want to sell their dedicated RTCs ;-) Sunish
On Tue, Feb 8, 2011 at 5:36 AM, funlw65(Vasi) <[email protected]> wrote: > Hmmm, Microchip are designing devices thinking with their legs and not > the brains... > > It seems to me that you can't use I2C, SPI and RTC same time : > ( (thinking at pins used to remap the second SPI) > > Here are three workarounds (target: logger applications): > 1. using an external RTCC - waste. > 2. using HW SPI with a SD card and I2C software - RTC on chip > 3. using HW I2C and software SPI with SD card - RTC on chip. > > Only the first one it appears to be reliable to me. > > I don't know an ATmega with RTC but ATmega644P have 2 USART, 1 SPI, 1 > I2C (TWI).. All are separated - have their own pins. > > On Feb 6, 6:02 pm, Sebastien Lelong <[email protected]> > wrote: > > 18F27J53 has two MSSP modules. MSSP1 can be used for both I²C and SPI, > while > > MSSP2 can only be used for SPI. Since I want i²C, and SPI for embedded > > sd-card, I²C must use RB4 and RB5 pins (pullups for SDA1 and SCL1). > > > > I thus need to use different pins for SPI. MSSP2 has remappable pins (RPn > > pins on datasheets, see screenshot). Interesting feature, I'm supposed to > > select whatever remappable pins needed for SPI... Need more thoughts, but > I > > think I'll remap them on RP2, RP11, RP12 and RP13. > > > > Datasheet reading......... > > > > [image: 18f27j53.png] > > > > Cheers, > > Seb > > > > 2011/2/6 Sebastien Lelong <[email protected]> > > > > > > > > > Hi Vasi, > > > > > 2011/2/6 funlw65(Vasi) <[email protected]> > > > > >> The board will be less general with the two 4k7 resistors on RB1-2... > > > > > Arf... These were supposed to be I²C pull-up resistors, but they aren't > > > connected to the correct pins ! Nice catch, thanks, I'll fix this asap > ! If > > > you don't want this feature, just don't solder resistors, that's the > idea. > > > > > BTW I tried to move traces and add more spaces as you suggested. I'll > post > > > the result soon. > > > > > cheers, > > > Seb > > > > -- > > Sébastien Lelonghttp://www.sirloon.nethttp://sirbot.org > > > > 18f27j53.png > > 56KViewDownload > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > > -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
