[time-nuts] Follow-up question re: microcontroller families

[Herbert Poetzl]

On Sun, May 26, 2013 at 07:46:38AM -0400, Bob Camp wrote:
> Hi

> On May 25, 2013, at 11:26 PM, Herbert Poetzl <herbert at 13thfloor.at> wrote:

>> On Sat, May 25, 2013 at 09:26:02PM -0400, Bob Camp wrote:
>>> Hi

>>> I realize this is a bit like water torture - sorry about that.

>>> If I go to Microchip Direct and ask for a PIC 18F with two
>>> UARTS and two A/D's I get the PIC18F86J72 and PIC 18F87J72.
>>> To me the second one is the obvious winner. It's got twice
>>> the flash for next to nothing more money. 1-25 piece price is
>>> $6.04.

>>> Same search, 1 A/D, 4 UARTS, lowest cost this time. PIC18F65J94
>>> is the winner. Lowest price package is $3.30 in 1-25 pieces.

>> 4 UARTS are untypical for PICs and result in higher price
>> as the device usually has more pins (which makes them more
>> expensive)

> The ARM that the thread was looking at was a 6 UART / 4 A/D
> part. Thus the "load up the UARTS". Also the starting point 
> for all this did involve serial i/o.

I have no idea for what 'home' project you would make
good use of 6 UARTs, but please don't get me wrong,
I'm using a lot of ARM/MIPS microcontrollers and
devices here, and I appreciate that they got really
cheap over the years.

But for many applications, the inevitable overhead
(power, heat, external components, OS, etc) simply 
eliminates the gain of having a better/faster CPU.

Sometimes I end up using a 6 or 8 pin PIC with only
a few lines of code to to solve complex problems where
a (F)PGA/CPLD design would be a lot of work and a 
16/32bit microcontroller simply overkill.

As always, YMMV, best,
Herbert

>>> Are those some *very* arbitrary choices - you bet they are.
>>> They are random picks, and were not optimized to show any
>>> particular thing. Only to target an application that had some
>>> serial i/o and a bit of A/D involvement.

>>> Bottom line - not all PIC's are $1. once you start adding
>>> peripherals. For $6 over in ARM land, you can get a lot of
>>> chip. To be fair, my experience has been that you can do better
>>> in the PIC24 line once you start adding stuff. Searching the
>>> PIC24's is hard enough that my brief search tonight did not
>>> show up a lower cost part.

>> PIC24F04KA200 1 UART, 10 ADC, XLP, 1.38 USD (1.05 USD @1k)
>> PIC24EP32GP202 2 UART, 6 ADC, 2.76 USD (1.86 USD @1k)

> I knew they had to be there. Again suggesting that the PIC24's probably are a better starting point these days.


>> One (dis)advantage of the Microchip PICs is that there
>> are so many different families and parts.

> Indeed

> Bob


>> best,
>> Herbert

>>> Bob

>>> On May 25, 2013, at 9:05 PM, Bob Camp <lists at rtty.us> wrote:

>>>> Hi

>>>> I just realized the "buy direct" button on that page requires a login. The single piece direct price is $9.70. First price break is at 25 pieces (to $8.95).

>>>> Bob

>>>> On May 25, 2013, at 8:56 PM, Bob Camp <lists at rtty.us> wrote:

>>>>> Hi

>>>>> It's one of the Freescale K60's they have them in several speeds and packages. Others have similar parts.

>>>>> http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=K60_120&nodeId=01624698C9DE2DDDAF&tab=Buy_Parametric_Tab&fromSearch=false

>>>>> hopefully shows the family information

>>>>> The first part on the list is the MK60FN1M0VLQ12 for 8% more money you can get the 150 MHz core rather than the 120 MHz core version. Both have enough pins that you can get at a lot of the peripherals at once. Both have enough pins that they are not a lot of fun to solder by hand. Of course their BGA cousins are even less hand solder friendly….

>>>>> Bob


>>>>> On May 25, 2013, at 6:48 PM, Graham / KE9H <timenut at austin.rr.com> wrote:

>>>>>> On 5/25/2013 3:40 PM, Bob Camp wrote:
>>>>>>> You can get a part with 1MB of flash, 128KB of ram, 6 UARTS, 4 16 bit A/D's, 10/100 Ethernet, USB, and a bunch of other stuff for less than $10. Drop this and that, go to half the flash, and yup, the price is 1/2. Comes with a free toolchain and two very capable free versions of RTOS.


>>>>>> Bob:

>>>>>> I was wondering which manufacturer/part you were referring to.

>>>>>> Thanks,
>>>>>> --- Graham

>>>>>> ==

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