381 Views 5 Replies Last post: Dec 22, 2009 4:56 AM by Michael-K. RSS
Erwin Hindriks Newbie 4 posts since
Dec 21, 2009
Currently Being Moderated

Dec 21, 2009 8:37 AM

setup compiler for 16 bit external data bus

I am using the H8s2318 micro and writing a programm in HEW.

 

I have setup the ABWCR register to use a 16 bit data bus, however when I write to a register on the connected FPGA it seems that a 16 bit value is written as two 8 bit values on two consecutive addresses.

The assembler code generated by the c compiler confirms this behaviour.

I have been looking everywhere in HEW to find an option to tell the compiler that it has to use a 16 bit data bus, but I couldn't find it. I have also tried using sections, but that also didn't give me an option to enter the data bus width.

 

I hope somebody can guide me in this.

Tags: external_data_bus
Michael-K. Newbie 33 posts since
Apr 16, 2009
Currently Being Moderated
Dec 22, 2009 1:54 AM in response to: Erwin Hindriks
Re: setup compiler for 16 bit external data bus

There are no settings in HEW.

 

Bus accesses to external bus is translated inside the µC. Exception: you request byte accesses to 16-bit buswidth.

So, please show us your C-code to output data to the FPGA and your ABWCR settings too.

Michael-K. Newbie 33 posts since
Apr 16, 2009
Currently Being Moderated
Dec 22, 2009 4:24 AM in response to: Erwin Hindriks
Re: setup compiler for 16 bit external data bus

Are you sure HEW uses the settings for H8S CPU?

I remember H8/3000 series, where you could use 1MB (or 16MB) memory space. Here address 0x50000 would direct to CS-area2 and not to CS-area0 as expected.

Michael-K. Newbie 33 posts since
Apr 16, 2009
Currently Being Moderated
Dec 22, 2009 4:56 AM in response to: Erwin Hindriks
Re: setup compiler for 16 bit external data bus

So please ignore my last thought.

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