Hello everyone
I am working on LPC2468 usb host with mass storage class . I am using NXP usb hostlite example as a base. I converted this source code for FAT32 system. It,s working fine for KIGNSTON 8 GB, SANDISK 4 GB pendrive. But when i used Hp 8 GB pendrive , it works fine sometime or sometime not.when I debug through the software the value of HOST_RhscIntr is not changing to 1. What,s the reason behind it.
today my pastor said "The PC in church can not read my power point on this pen drive" I said "Is it a HP stick" he replied "yes".
My best guess is that USB is becoming the new RS-232 where the manufacturers (or developers) save a penny by ignoring the specs and just state "this solution works with most".
Thus a HP stick that is 'just' within specs will not work on units that do not (in some respect) TOTALLY adhere.
It would be extremely interesting if the OP (or someone else) would diagnose this fully and find which end of the stick is wrong.
It may, of course. also be that by leaving HP sticks by the wayside, you gain some speed.
Erik
But when you buy memory cards, they are sold in many different speed classes. These speed classes obviously do affect how the card can be used...
True. But rogue cards almost do certainly occur. A while ago I had a collection of same supplier, same part number cards and found that two of that collection failed to work in various pieces of kit. Not just equipment that I had involvement in. They would even fail in some card readers but not others.
Lots of manufacturers buys batches of components when they build cards. So if you buy same article number, you can get totally different contents inside every time you buy.
They should all be working - if the manufacturer isn't directly stupid - but will very different specifications. Some fast, some slow. Some supporting many rewrites, some supporting few. Some having huge tolerances for supply voltages, while some needing very close to 5V.
Quite few card manufacturers have own flash manufacturing or buy same memory chips all the time from the same manufacturer.