Thank you for your prompt and helpful reply. CIL. On Mon, Sep 10, 2012 at 1:25 AM, Eric Decker <[email protected]> wrote:
> > > On Sun, Sep 9, 2012 at 9:39 PM, Xiaohui Liu <[email protected]> wrote: > >> Hello all, >> >> I have a few things uncertain about USART on TelosB. >> >> 1) This may be naive, but I'm really curious why USART is needed in the >> first place. Why can't the CPU talk to, say, CC2420 directly since they are >> wired >> together<http://webs.cs.berkeley.edu/tos/hardware/telos/telos-revb-2004-09-27.pdf> >> ? >> > > Huh? Well take a look at the 1611 data sheet. The USART hardware > provides various functions but not at the same time. The CPU talks to the > CC2420 through the USART as SPI. > > Read the TI data sheet and the user manual. And look at the telosb > schematic. > >From page 6 of the datasheet<http://www.ti.com/lit/ds/symlink/msp430f1611.pdf> showing functional block diagram of MSP430F16x, P3 and USART0 seem to be separated. But from the schematic<http://webs.cs.berkeley.edu/tos/hardware/telos/telos-revb-2004-09-27.pdf>, P3.1 is used as SIMO signal when USART0 is configured as SPI mode. Is this because in TelosB, USART0's SIMO pin is physically wired to P3.1? > > >> >> 2) What components/devices/peripherals are communicating with CPU via >> USART? Via which one (USART0 or USART1) and in which mode (UART, SPI, or >> I2C)? >> > > look at the schematic. > > USART0 is connected to CC2420 in SPI or I2C mode. Its UART mode is not used. USART1 is connected to USB in UART mode. Its SPI mode is not used. > >> 3) Can USART0 and USART1 be used in parallel? >> > > yes. look at the data sheet. > > >> For instance, can a strobe be sent to CC2420 using USART0 while the RSSI >> register on CC2420 is being read using USART1? >> > > huh again. I beleive a strobe is a message sent to the CC2420 but may > also use a directly wired pin. > > The cc2420 is wired via only one set of hardware so your suggestion is > non-sensical. > > >> >> Your explanation will be highly appreciated. >> >> -Xiaohui Liu >> >> >> _______________________________________________ >> Tinyos-help mailing list >> [email protected] >> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >> > > > > -- > Eric B. Decker > Senior (over 50 :-) Researcher > > > -- -Xiaohui Liu
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