Hi, Guys, the following story is specific to LH7A400 SoC.
> Yeah, it does. A 1 micro-second delay should do it, right? > I've also run into trouble with how picky the chip is. For > instance, the chip select and read signal must be deasserted > between reads. (see Fig. 31, pg 137 of the ISP1362 manual) If I > just don't write, it sometimes leaves chip-select asserted. So, I > can write to another chip select in the mean-time to force it to > change. Mike, I finally got an opportunity to attach a logic analyzer to the system bus and look at the behavior of CS, OE, and WE signals. I learned the following. 1. The (almost) optimal timing in my board is, when I configure the static memory controller's IDCY field to max (0xf) and add udelay(1) only into HC_ISP1362_WRITE_ADDR. However, with this setting I see that CS indeed remains active for several subsequent reads/writes. An access to another memory range relieves that problem. 2. If there is udelay(1) after every register access then the problem of CS remaining active between register accesses is gone (well, I haven't seen it). 3. The CS and OE signals on LH7A400 behave an unexpected way. Namely, while CS is asserted about 5ns before OE is asserted, the CS is also deasserted about 5ns before OE is deasserted. I.e., these signals remain active for the same amount of time, but just CS makes its cycle 5ns earlier than OE. This phenomenon is independent of the WST1 setting in BCR register. The datasheet of isp1160 says that OE may be deasserted before or together with CS. I have no idea, whether this can affect the behavior of the chip. Perhaps only somebody in Philips knows. The WE signal works as expected. It is asserted together with CS and deasserted 10ns before CS is deasserted. Olav ------------------------------------------------------- This SF.Net email is sponsored by: InterSystems CACHE FREE OODBMS DOWNLOAD - A multidimensional database that combines robust object and relational technologies, making it a perfect match for Java, C++,COM, XML, ODBC and JDBC. www.intersystems.com/match8 _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
