Re: How fast must be my flash memory for a 73 MHz Design of the tini board?
Robert Muchsel <robert.muchsel-6tN4nzCoH/[email protected]>
| Newsgroups | gmane.comp.hardware.microcontrollers.tini |
|---|---|
| Message-ID | <[email protected]> |
First of all, your memory must be fast enough. Here's some information how to calculate flash memory speed posted earlier: > [...] please use the following information: > > On page 27 of the AM29LV081B data sheet, look at the "output enable to > output delay" time, t_ELQV. It is 30ns for the 70ns part. This is the > timing that corresponds to "PSEN low to valid instruction in" on the > DS80C400. > > Another important DS80C400 characteristic is the address to valid data > in (t_AVIV1) which is 3*clcl - 19. In the case of 29.5MHz that > computes > to 82.5 ns (and this is not met by the 90ns flash). > > In other words, the 70ns flash allows you to run at 33MHz. The 90ns > flash at 27.5MHz. There is no available flash memory that will work at 75Mhz. You will have to copy your flash memory to an extra SRAM on boot (please see the list archives for more information) before enabling the DS80C400 clock multiplier. Second, the DS80C400 boot loader can only program flash devices that are 100% compatible with the AMD flash. You can easily work around this by using an external programmer or by loading your own loader into SRAM. Robert On Tue, 2004-03-16 at 08:00, Peter in Afrika wrote: > Hello, > > I am new here and I am actually composing my schematics for a 75 Mhz > version of the tini! > Because the Am29l040b-60R (which is on the network camera design) is > not available, I wanted to asked, what required minimum of flash access > time the AMD Memory MUST have? > > Can I use the AM29LV081B-90EC (that is the only one I found on the web) > which is on the evaluation kit? > Or does anybody of you have extra stock of AM29lv040b-60R or any larger > size of the same type? > > So finally: What types can I use for this fast design? > > Please answer, > > kind regards > Peter > > _______________________________________________ > TINI mailing list > TINI-6tN4nzCoH/[email protected] > To UNSUBSCRIBE, edit your profile, or see list archives: > http://lists.dalsemi.com/mailman/listinfo/tini -- Robert Muchsel - Dallas Semiconductor - http://www.maxim-ic.com/TINI/ _______________________________________________ TINI mailing list TINI-6tN4nzCoH/[email protected] To UNSUBSCRIBE, edit your profile, or see list archives: http://lists.dalsemi.com/mailman/listinfo/tini