OHX51: GENERATING HEX FILES FOR PHILIPS MX DEVICES

Information in this article applies to:

• C51 Version 7.06 or higher

QUESTION

I need to generate an Intel HEX file for the Philips 80C51MX device series. I noticed that the current version of OHX51 generates a hex file which starts the code in 0x000000. Previous versions generated the code starting at 0x800000.

Why was this changed and how can I generate a file that starts with the physical offset at 0x800000, as it was in the previous release?

ANSWER

Typically, a Philips 80C51MX device has a CODE ROM that starts with physical address 0 but is mapped to the logical CODE address that starts at address 0x800000. Since many customers were confused by the way HEX files were generated, the new version of OHX51 defaults to OFFSET(-0x800000) for the Philips 80C51MX devices.

To generate HEX files with the old address offset of 0x800000, you may invoke OHX51 from the command prompt using the OFFSET (0) directive.

Another alternative is to enter the following OHX51 command line into the Option for Target - Output dialog under Run User Program:

C:\KEIL\C51\BIN\OHX51.EXE "#L" H386 OFFSET (0)

MORE INFORMATION

• Application Note 160: Programming the Philips 51MX Architecture with the Keil PK51.
• Refer to the OHX51 User's Guide.

SEE ALSO

• C51: EXAMPLE PROGRAMS FOR THE PHILIPS MX DEVICES

Last Reviewed: Sunday, February 11, 2007