« Return to Thread: Linux x uClinux for ColdFires: what is the best for what?
Re: Linux x uClinux for ColdFires: what is the best for what?
by John Bodnar
::
Rate this Message:
Ricardo Raupp wrote:
No comments on the Linux questions, but...
> 2- If I not use DDR memory, only SD_DRAM or ordinary SRAM, the V2
> flex bus is pretty enough to it.
> Rigth or wrong?
Depends on which V2 device you use. FlexBus is not used on all of them.
Doesn't matter, though. You can bolt whatever external memory interface
is on a ColdFire device up to a SRAM.
But, do you really want to use SRAM? It's easy to interface, but
choices are limited, and SRAM no longer has the commodity pricing it had
back in the days when every 486 motherboard came with 128 or 256 Kbytes
of L2 cache.
> 4- Could someone explain me why / whnen should I use SDR / DDR / DDR2
> / Mobile etc..devices?It makes a difference
> when chosing between V2 x V4, rigth?
SDRAM gets you more RAM for less money. For a couple of dollars, you
can get 32 or 64 Mbytes of DDR1 SDRAM. To get that much SRAM, you'd
have to spend a lot more.
The type of SDRAM you use and the ColdFire core you use are totally
independent choices, except that some ColdFire devices support more
SDRAM types than others. Currently, the support is like this:
MCF523x family - 3.3V SDR only
MCF5270/1/2 family - 3.3V SDR only
MCF5274/5 family - DDR1 only
MCF528x family - 3.3V SDR only
MCF5207/8 - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF5227x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF532x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF537x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF547x family - 3.3V SDR and DDR1
MCF548x family - 3.3V SDR and DDR1
MCF5445x family - DDR1, DDR2, LPDDR (mobile)
LPDDR is the JEDEC standard name for Mobile DDR, which is essentially a
trade name used by Micron, Samsung, etc.
> 6- A V2 requirements, like pcb cares, powers, etc...is much(?) more
> simpler than a (full use) V4?
Not necessarily. Depends on operating frequency and what type of
SDRAM. Generally speaking, the ColdFire devices that we build intended
for use with SDRAM require multiple supply voltages. The MCU devices we
produce have internal flash and SRAM, usually do not support SDRAM, and
require just one voltage level.
-- John
> ----- Original Message ----- From: "John Bodnar"
> <john.bodnar@...>
> To: "Ricardo" <ricardo@...>
> Sent: Thursday, May 01, 2008 3:12 PM
> Subject: Re: [ColdFire] Linux x uClinux for ColdFires: what is the
> best for what?
>
>
>> David Brown wrote:
>>> With higher frequency and higher performance devices, you have to
>>> take more care with your memories and buses, and you have more
>>> worries about your power supplies and decoupling. You often need
>>> more voltage levels (the v4 has 1.5V for the core, 1.8/2.5V for the
>>> memory buses, and 3.3V for IO - the 5234 with which I am most
>>> familiar has 1.5V core and everything else at 3.3V). It is
>>> typically easier on slower devices to attach other peripherals to
>>> the external buses without glue logic, level converters, etc.
>>
>> Well, therein lies the rub. As soon as you start supporting DDR of
>> any kind, you get away from being able to produce a device with only
>> two voltage rails. The MCF523x family only supports SDR, so it never
>> had a reason to support other than just I/O and VDD supplies.
>>
>> The MCF5445x still maintains a 3.3V general-purpose memory bus
>> (FlexBus) for connecting up everything else but your SDRAM. In the
>> future, I'm looking to move the FlexBus to its own dedicated supply
>> rail in order to support flashes and FPGAs/CPLDs with 1.8V I/Os as a
>> means of reducing I/O power. This would up the number of supply
>> rails to four (core, SDRAM, FlexBus, and digital I/O), but you could
>> still run the FlexBus at 3.3V, if desired.
>>
>>> I haven't used any v4 cores, so my rough comments are only based on
>>> my reading of datasheets and application notes. But our move from
>>> the older, slower MC68832 to the MCF5234 required a bit step in
>>> board complexity and quality - I would plan for another step up,
>>> though perhaps not as large, in doing a v4 board.
>>
>> I think we've made the MCF5445x family quite friendly for board
>> design, especially on the 256-ball MAPBGA variants. We're trying to
>> take the lessons we've learned from doing the package and substrate
>> design for those devices and apply them to new higher end parts going
>> forward.
>>
>>> I you want to tell me that I'm wrong, and that the MCF5445x is as
>>> easy to use as the MCF5234 (baring the lack of a TPU), then go ahead
>>> - I'll listen! I like the ColdFire architecture, and if the v4 will
>>> give me a lot more processing power for little more complexity, then
>>> it's definitely good to know.
>>
>> I think I mentioned it before, but I am hardly an expert on board
>> design, so I could be wrong on all counts :-( That said, I had
>> plenty of help from some real experts on the MCF5445x, so I think
>> we've made that family one of our better examples of how to pin out
>> and package a device. Of course, by saying as much, I'm now setting
>> myself up for pot shots from the peanut gallery, so let the shooting
>> commence :-)
>>
>> John Bodnar
>> Systems Engineer
>> Microcontroller Solutions Group
>> Freescale Semiconductor, Inc.
>>
>> --
>> POPI Classification
>> [ ]General Business Information
>> [x]Freescale Internal Use [ ]Freescale Confidential Proprietary
>>
>> ---
>> coldfire@... Send a post to the list.
>> coldfire-join@... Join the list.
>> coldfire-digest@... Join the list in digest mode.
>> coldfire-leave@... Leave the list.
>>
>>
>>
>> __________ NOD32 3067 (20080430) Information __________
>>
>> This message was checked by NOD32 antivirus system.
>> http://www.eset.com
>>
>>
>
> ---
> coldfire@... Send a post to the list.
> coldfire-join@... Join the list.
> coldfire-digest@... Join the list in digest mode.
> coldfire-leave@... Leave the list.
>
--
POPI Classification
[ ]General Business Information
[x]Freescale Internal Use
[ ]Freescale Confidential Proprietary
---
coldfire@... Send a post to the list.
coldfire-join@... Join the list.
coldfire-digest@... Join the list in digest mode.
coldfire-leave@... Leave the list.
No comments on the Linux questions, but...
> 2- If I not use DDR memory, only SD_DRAM or ordinary SRAM, the V2
> flex bus is pretty enough to it.
> Rigth or wrong?
Depends on which V2 device you use. FlexBus is not used on all of them.
Doesn't matter, though. You can bolt whatever external memory interface
is on a ColdFire device up to a SRAM.
But, do you really want to use SRAM? It's easy to interface, but
choices are limited, and SRAM no longer has the commodity pricing it had
back in the days when every 486 motherboard came with 128 or 256 Kbytes
of L2 cache.
> 4- Could someone explain me why / whnen should I use SDR / DDR / DDR2
> / Mobile etc..devices?It makes a difference
> when chosing between V2 x V4, rigth?
SDRAM gets you more RAM for less money. For a couple of dollars, you
can get 32 or 64 Mbytes of DDR1 SDRAM. To get that much SRAM, you'd
have to spend a lot more.
The type of SDRAM you use and the ColdFire core you use are totally
independent choices, except that some ColdFire devices support more
SDRAM types than others. Currently, the support is like this:
MCF523x family - 3.3V SDR only
MCF5270/1/2 family - 3.3V SDR only
MCF5274/5 family - DDR1 only
MCF528x family - 3.3V SDR only
MCF5207/8 - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF5227x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF532x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF537x family - 1.8, 2.5, 3.3V SDR, DDR1, LPDDR (mobile)
MCF547x family - 3.3V SDR and DDR1
MCF548x family - 3.3V SDR and DDR1
MCF5445x family - DDR1, DDR2, LPDDR (mobile)
LPDDR is the JEDEC standard name for Mobile DDR, which is essentially a
trade name used by Micron, Samsung, etc.
> 6- A V2 requirements, like pcb cares, powers, etc...is much(?) more
> simpler than a (full use) V4?
Not necessarily. Depends on operating frequency and what type of
SDRAM. Generally speaking, the ColdFire devices that we build intended
for use with SDRAM require multiple supply voltages. The MCU devices we
produce have internal flash and SRAM, usually do not support SDRAM, and
require just one voltage level.
-- John
> ----- Original Message ----- From: "John Bodnar"
> <john.bodnar@...>
> To: "Ricardo" <ricardo@...>
> Sent: Thursday, May 01, 2008 3:12 PM
> Subject: Re: [ColdFire] Linux x uClinux for ColdFires: what is the
> best for what?
>
>
>> David Brown wrote:
>>> With higher frequency and higher performance devices, you have to
>>> take more care with your memories and buses, and you have more
>>> worries about your power supplies and decoupling. You often need
>>> more voltage levels (the v4 has 1.5V for the core, 1.8/2.5V for the
>>> memory buses, and 3.3V for IO - the 5234 with which I am most
>>> familiar has 1.5V core and everything else at 3.3V). It is
>>> typically easier on slower devices to attach other peripherals to
>>> the external buses without glue logic, level converters, etc.
>>
>> Well, therein lies the rub. As soon as you start supporting DDR of
>> any kind, you get away from being able to produce a device with only
>> two voltage rails. The MCF523x family only supports SDR, so it never
>> had a reason to support other than just I/O and VDD supplies.
>>
>> The MCF5445x still maintains a 3.3V general-purpose memory bus
>> (FlexBus) for connecting up everything else but your SDRAM. In the
>> future, I'm looking to move the FlexBus to its own dedicated supply
>> rail in order to support flashes and FPGAs/CPLDs with 1.8V I/Os as a
>> means of reducing I/O power. This would up the number of supply
>> rails to four (core, SDRAM, FlexBus, and digital I/O), but you could
>> still run the FlexBus at 3.3V, if desired.
>>
>>> I haven't used any v4 cores, so my rough comments are only based on
>>> my reading of datasheets and application notes. But our move from
>>> the older, slower MC68832 to the MCF5234 required a bit step in
>>> board complexity and quality - I would plan for another step up,
>>> though perhaps not as large, in doing a v4 board.
>>
>> I think we've made the MCF5445x family quite friendly for board
>> design, especially on the 256-ball MAPBGA variants. We're trying to
>> take the lessons we've learned from doing the package and substrate
>> design for those devices and apply them to new higher end parts going
>> forward.
>>
>>> I you want to tell me that I'm wrong, and that the MCF5445x is as
>>> easy to use as the MCF5234 (baring the lack of a TPU), then go ahead
>>> - I'll listen! I like the ColdFire architecture, and if the v4 will
>>> give me a lot more processing power for little more complexity, then
>>> it's definitely good to know.
>>
>> I think I mentioned it before, but I am hardly an expert on board
>> design, so I could be wrong on all counts :-( That said, I had
>> plenty of help from some real experts on the MCF5445x, so I think
>> we've made that family one of our better examples of how to pin out
>> and package a device. Of course, by saying as much, I'm now setting
>> myself up for pot shots from the peanut gallery, so let the shooting
>> commence :-)
>>
>> John Bodnar
>> Systems Engineer
>> Microcontroller Solutions Group
>> Freescale Semiconductor, Inc.
>>
>> --
>> POPI Classification
>> [ ]General Business Information
>> [x]Freescale Internal Use [ ]Freescale Confidential Proprietary
>>
>> ---
>> coldfire@... Send a post to the list.
>> coldfire-join@... Join the list.
>> coldfire-digest@... Join the list in digest mode.
>> coldfire-leave@... Leave the list.
>>
>>
>>
>> __________ NOD32 3067 (20080430) Information __________
>>
>> This message was checked by NOD32 antivirus system.
>> http://www.eset.com
>>
>>
>
> ---
> coldfire@... Send a post to the list.
> coldfire-join@... Join the list.
> coldfire-digest@... Join the list in digest mode.
> coldfire-leave@... Leave the list.
>
--
POPI Classification
[ ]General Business Information
[x]Freescale Internal Use
[ ]Freescale Confidential Proprietary
---
coldfire@... Send a post to the list.
coldfire-join@... Join the list.
coldfire-digest@... Join the list in digest mode.
coldfire-leave@... Leave the list.
« Return to Thread: Linux x uClinux for ColdFires: what is the best for what?
| Free embeddable forum powered by Nabble | Forum Help |
