Problem of booting from EPROM

Started by Devi Prasad April 28, 2000
Hi all,

    I have  a project with ADSP-21060 ( SHARC) as the processor with   Mil-1553B interface. The project involves EPROM
booting through the external port( through a Flash memory or EPROM )

    The clock_in for sharc processor is 40 MHz  and that for Mil-1553B processor is 20MHz.  The /READY( which is active
low ) line from the Mil-1553B processor is inverted and connected to the ACK line of the SHARC  processor. The /READY
line will be high during the data transfer between  SHARC and MIL-1553B processor and goes low only when the data
transfer is complete. This configuration works fine when the program is loaded through the JTAG Port ( EZ-ICE).

    But when I try to boot the SHARC from a EPROM or  FLASH memory using the same code ( obiously after generating
.bin file ) with the above configuration, the SHARC doesn't boot  since it is asserting ACK low  ( becoz MIL-1553B device
drives the ACK low during EPROM boot). As mentioned in the ADSP-21060 User's Manual i have changed the value in the
WAIT  register , setting the UBWM value to the internal wait mode (01) at the location 0x0002 0005.  But still the SHARC
doesn't boot...

 I followed the following steps while generating the .bin file

1.In the 060_prom.asm file in the vector table for___lib _RSTI ( i.e., location 0x0002 0005 ) the following code has been

    r0 =  0x219ce739;
    dm(0x2) = r0;

2. I generated 060_prom.obj and 060_prom.exe and linked with my program to generate a .bin file.

3. I then loaded this .bin file to a FLASH memory , and tried to boot the SHARC with this code.  But was unsuccessful.

    During this i observed the following.

        *  ACK was low.
        *  /BMS was continuously low....It was not going high..

I am using only /MS0 ( DM0 bank) and  /MS1( DM1 bank )  memory select lines ( Infact /MS1 is connected to the
MIL-1553B processor ).

For  DM0 bank we require only internal wait states and for DM1 bank wait state mode is External acknowlegde only.
Hope to get a solution soon....


Devi Prasad
Systems Engineer
Accord Software & Systems Pvt. Ltd.
Domlur Layout

Ph : 5560105/136/138 extn : 233