On 5/2/11, JMGross <msp...@grossibaer.de> wrote: > > There are two versions of the L092. > The development version has a ROM based bootloader for loading > the application from an external SPI flash. > The ohter one has the boot loader replaced by a mask-programmed > ROM with the actual application and does not need the external > flash anymore. > The reason why there is no internal flash is htat the flash technology > used by TI in the other MSPs requires a much higher operating > voltage (not to count the programming voltage). > So the version with bootloader doesn't make much sense as a > low-voltage version, if you still require the usually much higher > supply voltage for the external flash.
As described in SLAU321 (p. 187) the development version's loader starts by outputting a pulse train on a pin, for the external charge pump that produces enough voltage for an external SPI memory that the bootloader then reads in. I think that is enough for a small standalone system. As you say, the ROM version requires several k$ NRE and coordination with TI that would not make sense for small volume projects. > I suggested that they produce a part where there is internal > flash and a bootloader that copies from flash to RAM before > deactivating the internal flash and the voltage regulators, so > the part can be run from a single LV supply while still being > able to be programmed 'normally'. > AFAIK there's no flash that works off 0.9V, even for reading. I think there needs to be a charge pump of some sort. I think it would work if the MSP contained an open collector high-voltage transistor and a diode, feeding an external capacitor that provides 3V supply for the on-chip flash, temporarily, while it's being transfered to RAM. ------------------------------------------------------------------------------ WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution. http://p.sf.net/sfu/whatsupgold-sd _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users
