Wouldn't you think that would be an easy question to answer? Ha ha! On the TMS570, you set up "data formats" using HAL. Data format 1 is currently set up to 10MHz, and the others are set to 1MHz. Then tracking back through the code, the MRAM uses data format 1, so it is running at 10MHz. The DCT (Digital Communications Tranceiver, that is the AX5043) has its SPI at 1MHz. As I recall, I increased the MRAM speed largely because on Golf there was a lot more data being sent (the Whole Orbit Data) relatively regularly. I could look back at Fox, which saves much less data in MRAM, if you care.

Just a comment re the MRAM: It's only clock is the SPI Clock which says to me that the clock speed only makes a difference while there is communication on the bus. I'd think that would be a relatively small % of the time, right? Or am I really missing something?

73,

Burns Fisher, WB1FJ

AMSAT(R) Engineering -- Flight Software

On Fri, Nov 18, 2022 at 10:07 AM Jim McCullers <wa4cwi@bellsouth.net> wrote:

We need to address Pacsat memory considerations.

The MR25H40 is arranged as 8 x 512k bytes and is SPI.
The higher capacity models are parallel interface that would significantly complicate the design and board space.
In addition, they operate at much higher power consumption than the MR25H40.

With multiple MR25H40s there will de design issues with the file system when crossing memory bounds.

Burns or Rich, do you know what speed you are clocking the MR25H40?
There is considerable difference in power consumption between clocking speeds of 1mhz and 40mhz.

Thanks

Jim McCullers
WA4CWI
-----------------------------------------------
pacsat-dev mailing list -- pacsat-dev@amsat.org
View archives of this mailing list at https://mailman.amsat.org/hyperkitty/list/pacsat-dev@amsat.org
To unsubscribe send an email to pacsat-dev-leave@amsat.org
Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org