[ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Marcel Ovidiu Achim]

Andrew Lunn schrieb:

> On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
>  
>
>> Hi all,
>>
>> I am using eCos on an Atmel EB55 board. For an application I need to
>> store data into the on board flash device. My compiled code seams to
>> do an unaligned access to the on board flash which is enabled by the
>> NCS0 line.
>>
>> This is a very simple code for a better understanding.
>>
>> // Set the EBI_CSR0 register for 16 bit access etc.
>> HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
>>
>> // Write 0xAA to address 0x555 of into the flash device.
>> // Note: this is not the whole prog. seq.
>> HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
>>   
>
>
> I don't think this is allowed. You have to do 16 bit accesses on 16
> bit aligned addresses. Maybe you want to do:
>
> HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
> HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
>
> which will acheive the same but will do it in a legal way.
>
>        Andrew
>
>  
>

Your sugestion drives the NCS0 line twice and again the access is not 
alligned
(both read and write of the AT91 starts from A0 instead of A1). Since 
the memory cells of the flash
device are 16 bit long, while writing 0x556 means also writng to another 
cell instead
of 0x555.

Please give more advice.

Marcel

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[ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Marcel Ovidiu Achim]

Andrew Lunn schrieb:

> On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
>  
>
>> Hi all,
>>
>> I am using eCos on an Atmel EB55 board. For an application I need to
>> store data into the on board flash device. My compiled code seams to
>> do an unaligned access to the on board flash which is enabled by the
>> NCS0 line.
>>
>> This is a very simple code for a better understanding.
>>
>> // Set the EBI_CSR0 register for 16 bit access etc.
>> HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
>>
>> // Write 0xAA to address 0x555 of into the flash device.
>> // Note: this is not the whole prog. seq.
>> HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
>>   
>
>
> I don't think this is allowed. You have to do 16 bit accesses on 16
> bit aligned addresses. Maybe you want to do:
>
> HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
> HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
>
> which will acheive the same but will do it in a legal way.
>
>        Andrew
>
>  
>

Your sugestion drives the NCS0 line twice and again the access is not 
alligned
(both read and write of the AT91 starts from A0 instead of A1). Since 
the memory cells of the flash
device are 16 bit long, while writing 0x556 means also writng to another 
cell instead
of 0x555.

Please give more advice.

Marcel

-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss

Re: [ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Andrew Lunn]

On Sat, May 07, 2005 at 10:26:57AM +0200, Marcel Ovidiu Achim wrote:
> Andrew Lunn schrieb:
> 
> >On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
> > 
> >
> >>Hi all,
> >>
> >>I am using eCos on an Atmel EB55 board. For an application I need to
> >>store data into the on board flash device. My compiled code seams to
> >>do an unaligned access to the on board flash which is enabled by the
> >>NCS0 line.
> >>
> >>This is a very simple code for a better understanding.
> >>
> >>// Set the EBI_CSR0 register for 16 bit access etc.
> >>HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
> >>
> >>// Write 0xAA to address 0x555 of into the flash device.
> >>// Note: this is not the whole prog. seq.
> >>HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
> >>  
> >
> >
> >I don't think this is allowed. You have to do 16 bit accesses on 16
> >bit aligned addresses. Maybe you want to do:
> >
> >HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
> >HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
> >
> >which will acheive the same but will do it in a legal way.
> >
> >       Andrew
> >
> > 
> >
> 
> Your sugestion drives the NCS0 line twice and again the access is not 
> alligned
> (both read and write of the AT91 starts from A0 instead of A1). Since 
> the memory cells of the flash
> device are 16 bit long, while writing 0x556 means also writng to another 
> cell instead
> of 0x555.
> 
> Please give more advice.

How do you have the MMU setup for that area of memory?

        Andrew

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Re: [ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Andrew Lunn]

On Sat, May 07, 2005 at 10:26:57AM +0200, Marcel Ovidiu Achim wrote:
> Andrew Lunn schrieb:
> 
> >On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
> > 
> >
> >>Hi all,
> >>
> >>I am using eCos on an Atmel EB55 board. For an application I need to
> >>store data into the on board flash device. My compiled code seams to
> >>do an unaligned access to the on board flash which is enabled by the
> >>NCS0 line.
> >>
> >>This is a very simple code for a better understanding.
> >>
> >>// Set the EBI_CSR0 register for 16 bit access etc.
> >>HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
> >>
> >>// Write 0xAA to address 0x555 of into the flash device.
> >>// Note: this is not the whole prog. seq.
> >>HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
> >>  
> >
> >
> >I don't think this is allowed. You have to do 16 bit accesses on 16
> >bit aligned addresses. Maybe you want to do:
> >
> >HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
> >HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
> >
> >which will acheive the same but will do it in a legal way.
> >
> >       Andrew
> >
> > 
> >
> 
> Your sugestion drives the NCS0 line twice and again the access is not 
> alligned
> (both read and write of the AT91 starts from A0 instead of A1). Since 
> the memory cells of the flash
> device are 16 bit long, while writing 0x556 means also writng to another 
> cell instead
> of 0x555.
> 
> Please give more advice.

How do you have the MMU setup for that area of memory?

        Andrew

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Re: [ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Marcel Ovidiu Achim]

Andrew Lunn schrieb:

>On Sat, May 07, 2005 at 10:26:57AM +0200, Marcel Ovidiu Achim wrote:
>  
>
>>Andrew Lunn schrieb:
>>
>>    
>>
>>>On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
>>>
>>>
>>>      
>>>
>>>>Hi all,
>>>>
>>>>I am using eCos on an Atmel EB55 board. For an application I need to
>>>>store data into the on board flash device. My compiled code seams to
>>>>do an unaligned access to the on board flash which is enabled by the
>>>>NCS0 line.
>>>>
>>>>This is a very simple code for a better understanding.
>>>>
>>>>// Set the EBI_CSR0 register for 16 bit access etc.
>>>>HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
>>>>
>>>>// Write 0xAA to address 0x555 of into the flash device.
>>>>// Note: this is not the whole prog. seq.
>>>>HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
>>>> 
>>>>        
>>>>
>>>I don't think this is allowed. You have to do 16 bit accesses on 16
>>>bit aligned addresses. Maybe you want to do:
>>>
>>>HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
>>>HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
>>>
>>>which will acheive the same but will do it in a legal way.
>>>
>>>      Andrew
>>>
>>>
>>>
>>>      
>>>
>>Your sugestion drives the NCS0 line twice and again the access is not 
>>alligned
>>(both read and write of the AT91 starts from A0 instead of A1). Since 
>>the memory cells of the flash
>>device are 16 bit long, while writing 0x556 means also writng to another 
>>cell instead
>>of 0x555.
>>
>>Please give more advice.
>>    
>>
>
>How do you have the MMU setup for that area of memory?
>
>        Andrew
>
>  
>
Well, the only way to set the memory behaviour that I konw is to 
configure the EBI_CSR0 register.
I set it up as follows.

// Set the EBI_CSR0 register for 16 bit access etc.
HAL_WRITE_UINT32(0xFFE00000, BA_0x010 | CSEN | EBI_BAT_BYTE_SELECT | EBI_TDF_0 | 4MB_PAGE | WSE | EBI_NWS_1 | EBI_DBW_16);







-- 
Mit freundlichen Grüssen / Best regards

Marcel Ovidiu Achim

OVIDIUS Ingenieurbüro
Vogelsangstr. 76
70197 Stuttgart/Germany

Tel.: +49 (0)711 62 03 600
Mobil: +49 (0)177 69 070 59
email: marcel.achim@ovidius-ib.de


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Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss

Re: [ECOS] Re: unaligned half-word flash memory access on a EB55/AT91

[Marcel Ovidiu Achim]

Andrew Lunn schrieb:

>On Sat, May 07, 2005 at 10:26:57AM +0200, Marcel Ovidiu Achim wrote:
>  
>
>>Andrew Lunn schrieb:
>>
>>    
>>
>>>On Fri, May 06, 2005 at 08:51:17PM +0200, Marcel Ovidiu Achim wrote:
>>>
>>>
>>>      
>>>
>>>>Hi all,
>>>>
>>>>I am using eCos on an Atmel EB55 board. For an application I need to
>>>>store data into the on board flash device. My compiled code seams to
>>>>do an unaligned access to the on board flash which is enabled by the
>>>>NCS0 line.
>>>>
>>>>This is a very simple code for a better understanding.
>>>>
>>>>// Set the EBI_CSR0 register for 16 bit access etc.
>>>>HAL_WRITE_UINT32(0xFFE00000, 0x010030A1);
>>>>
>>>>// Write 0xAA to address 0x555 of into the flash device.
>>>>// Note: this is not the whole prog. seq.
>>>>HAL_WRITE_UINT16(0x01000000 + 0x555, 0xAA);
>>>> 
>>>>        
>>>>
>>>I don't think this is allowed. You have to do 16 bit accesses on 16
>>>bit aligned addresses. Maybe you want to do:
>>>
>>>HAL_WRITE_UINT8(0x01000000 + 0x555, 0xAA);
>>>HAL_WRITE_UINT8(0x01000000 + 0x556, 0x00);
>>>
>>>which will acheive the same but will do it in a legal way.
>>>
>>>      Andrew
>>>
>>>
>>>
>>>      
>>>
>>Your sugestion drives the NCS0 line twice and again the access is not 
>>alligned
>>(both read and write of the AT91 starts from A0 instead of A1). Since 
>>the memory cells of the flash
>>device are 16 bit long, while writing 0x556 means also writng to another 
>>cell instead
>>of 0x555.
>>
>>Please give more advice.
>>    
>>
>
>How do you have the MMU setup for that area of memory?
>
>        Andrew
>
>  
>
Well, the only way to set the memory behaviour that I konw is to 
configure the EBI_CSR0 register.
I set it up as follows.

// Set the EBI_CSR0 register for 16 bit access etc.
HAL_WRITE_UINT32(0xFFE00000, BA_0x010 | CSEN | EBI_BAT_BYTE_SELECT | EBI_TDF_0 | 4MB_PAGE | WSE | EBI_NWS_1 | EBI_DBW_16);







-- 
Mit freundlichen Grüssen / Best regards

Marcel Ovidiu Achim

OVIDIUS Ingenieurbüro
Vogelsangstr. 76
70197 Stuttgart/Germany

Tel.: +49 (0)711 62 03 600
Mobil: +49 (0)177 69 070 59
email: marcel.achim@ovidius-ib.de


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss