[ECOS] MCF5282 - bits for DACRx registers

Christian Meusel christian.meusel@inf.tu-dresden.de
Mon Feb 9 18:51:00 GMT 2009


I'm currently backporting our eCos port for the ColdFire MCF5282 (based 
on the old coldfire architecture) to the MCF52xx processor HAL (based on 
m68k) contributed by eCosCentric.

The archictecture HAL for MCF52xx processors provides quite a lot of 
definitions for the MCF5282. Amongst others, bit definitions for the 
SDRAM controller's DACR registers where the motivation behind is not 
clear to me. For example, the port size bits 
(HAL_MCFxxxx_SDRAMC_DACRx_PS_32, ...) are alredy shifted to the 
appropriate position within a DACR register where the command and bank 
MUX bits (HAL_MCFxxxx_SDRAMC_DACRx_CBM) are not.

Is there a special intention for not shifting the command and bank MUX 
bits to their appropriate position? Has these definitions be made for 
allowing to redefine HAL_MCFxxxx_SDRAMC_DACRx_CBM_SHIFT for other 
ColdFire processors? Is there already productive code out there which 
relies on this definition of the command and bank MUX bits?

If not, I would like to change the bit defintions for the command and 
bank MUX bits in var_io.h. If there is a reason for not doing so, our 
MCF5282 port will live with the definitions already provided for this 
bits. We are planning to contribute this port when it is finished and 
therefor  we would like to minimize the impact of such "global" changes.

Best regards,


Christian Meusel
TU Dresden
Fakultät für Informatik
Professur Mikrorechner

Internet: www.mr.inf.tu-dresden.de
Telefon: +49 351 463-37902
Telefax: +49 351 463-38245

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