----- Original Message -----
From: "Grant Edwards"
To: m...
Sent: Wednesday, October 10, 2007 2:28:06 PM (GMT-0700) America/Denver
Subject: [msp430] Small msp430 part w/ UART + SPI?
I'm trying to find a small MSP430 part that has both a UART and
SPI hardware (1 each). I need 2KB of flash and 256B of RAM and
about 5 I/O lines (in addition to the UART/SPI). Small size is
important.
I've been fighting with the the part selector web page for a
while and haven't been able to find such a part. But, it
doesn't seem possible to specify 1 SPI and 1 UART, so I may
have missed something.
Is anybody aware of a small part with both a UART and an SPI
interface?
--
Grant Edwards grante Yow! I'm encased in the
at lining of a pure pork
visi.com sausage!!
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not to be unpopular, but what about using Freescale MC9S08QG8?
It seems me to have everything: spi, uart, small size, low cost.
Also Renesas R8C14 is interesting, but it's a bit bigger in size.
I normally prefer MSP430, but sometime...
Andrea
--- In m..., Grant Edwards wrote: >
> On 2007-10-10, Aaron Greer wrote:
>
> >> It's very easy to bit-bash SPI. Particularly if you are
> >> Master.
>
> I'm not. The SPI interface would be as a slave to a device
> that's runnnig a HW SPI interface at with a clock rate in the
> hundreds of KHz.
>
> >> Also TimerA is very good at a cycle-accurate UART.
>
> I need to dedicate one 16-bit timer to a particular function.
>
> In some projects I've used the WD/interval timer to bit-bang a
> UART, but when you do that, you've only got 1 bit time to
> handle a received a byte. On this project that's only going to
> be a few hundred instructions, and I don't think that's going
> to be enough.
>
> >> So you could use F2011, and have both SPI & UART with S/w
> >> trickery ~300bytes of code (NB This is NOT a CPU cycle timed
> >> S/w-UART), but the USI on F20x2 is probably an easier reach.
>
> > Let's keep this in the list if we can.
>
> Please.
>
> > I think the OP wants to have both SPI and UART at the same
> > time. Using the USI won't get him that. Maybe a combo of USI
> > and SW bit bash would though.
>
> I don't think bit-banging a UART is going to be feasible. It
> would have to be done on a polling basis (the function to which
> the 16-bit timer is dedicated can't tolerate any interrupt
> latency at all), so all foreground processing would have to be
> done in increments less than one-bit-time long (chunks on the
> order of 400 clock cycles). In theory, that might be possible,
> but it would be pretty difficult.
>
> --
> Grant Edwards grante Yow! Kids, don't gross me > at
off ... "Adventures with > visi.com
MENTAL HYGIENE" can be >
carried too FAR!
>
Reply by Grant Edwards●October 10, 20072007-10-10
On 2007-10-10, Aaron Greer wrote:
> AFAIK the USCI will handle one each of UART and
SPI.
That's the way I read the datasheet. I had never realized that
it could do both at the same time (haven't used a part with a
USCI yet).
With a hardware UART, my foreground stuff only has to happen in
byte-time chunks instead of bit-time chunks. That makes life a
lot easier...
--
Grant Edwards grante Yow! What a COINCIDENCE!
at I'm an authorized
"SNOOTS
visi.com OF THE STARS" dealer!!
Reply by Microbit●October 10, 20072007-10-10
> _expensive_, and with AVRs interrupt handling and
dealing with
> 16-bit timer values leaves a lot to be desired.
Fun, ain't it ? :-)
Reads and writes have opposite byte order on the timer.
I just wrote low level handlers for that and then forget about it.
That is, after you've tried to make sense of the Mega jungle :-)
Best Regards,
Kris
-----Original Message-----
From: m... [mailto:m...] On Behalf Of Grant Edwards
Sent: Thursday, 11 October 2007 7:33 AM
To: m...
Subject: [msp430] Re: Small msp430 part w/ UART + SPI?
On 2007-10-10, Microbit wrote: > Hi Grant,
>
> AFAIK you have to turn to the bigger buggers because SPI is
> treated as a USART, unless I've missed some newer part.
Some of the smaller parts have a USI (which will do SPI or
I2C), but I also need a UART.
> But I guess you already knew that / were afraid of
that :-) I
> guess that's where little buggers like the AVR are good, they
> always come with SPI HW regardless of other periphs.
Yea, I've been looking at the ATtiny48 family but they're
_expensive_, and with AVRs interrupt handling and dealing with
16-bit timer values leaves a lot to be desired.
--
Grant Edwards grante Yow! Is it 1974?
What's
at for SUPPER? Can I spend
visi.com my COLLEGE FUND in one
wild afternoon??
Reply by Grant Edwards●October 10, 20072007-10-10
On 2007-10-10, elruocch wrote:
> not to be unpopular, but what about using Freescale
MC9S08QG8?
> It seems me to have everything: spi, uart, small size, low
> cost.
Thanks, I'll take a look at it.
> Also Renesas R8C14 is interesting, but it's a
bit bigger in
> size. I normally prefer MSP430, but sometime...
An MSP430 solution would be the easiest since I've got quite a
bit of the code already running, but other architectures are
always an option.
--
Grant Edwards grante Yow! Are the STEWED PRUNES
at still in the HAIR DRYER?
visi.com
Reply by Microbit●October 10, 20072007-10-10
> Yow! Hey, wait
> a minute!! I want a
> divorce!! ... you're not
> Clint Eastwood!!
.. Marriage is a sentence, not a word :-)
Best Regards,
Kris
-----Original Message-----
From: m... [mailto:m...] On Behalf Of Grant Edwards
Sent: Thursday, 11 October 2007 7:50 AM
To: m...
Subject: [msp430] Re: Small msp430 part w/ UART + SPI?
Reply by Grant Edwards●October 10, 20072007-10-10
On 2007-10-10, Aaron Greer wrote:
>> It's very easy to bit-bash SPI. Particularly if
you are
>> Master.
I'm not. The SPI interface would be as a slave to a device
that's runnnig a HW SPI interface at with a clock rate in the
hundreds of KHz.
>> Also TimerA is very good at a cycle-accurate
UART.
I need to dedicate one 16-bit timer to a particular function.
In some projects I've used the WD/interval timer to bit-bang a
UART, but when you do that, you've only got 1 bit time to
handle a received a byte. On this project that's only going to
be a few hundred instructions, and I don't think that's going
to be enough.
>> So you could use F2011, and have both SPI & UART
with S/w
>> trickery ~300bytes of code (NB This is NOT a CPU cycle timed
>> S/w-UART), but the USI on F20x2 is probably an easier reach.
> Let's keep this in the list if we can.
Please.
> I think the OP wants to have both SPI and UART at the
same
> time. Using the USI won't get him that. Maybe a combo of USI
> and SW bit bash would though.
I don't think bit-banging a UART is going to be feasible. It
would have to be done on a polling basis (the function to which
the 16-bit timer is dedicated can't tolerate any interrupt
latency at all), so all foreground processing would have to be
done in increments less than one-bit-time long (chunks on the
order of 400 clock cycles). In theory, that might be possible,
but it would be pretty difficult.
--
Grant Edwards grante Yow! Kids, don't gross
me
at off ... "Adventures with
visi.com MENTAL HYGIENE" can be
carried too FAR!
Reply by Grant Edwards●October 10, 20072007-10-10
On 2007-10-10, Aaron Greer wrote:
> True, it is a bit larger than a 14 pin TSSOP. But
it's only
> about 6mm on a side for the 40 pin QFN.
You're right. I was thinking of the 38-pin TSSOP.
> The 14-TSSOP is about 6.5 by 5.1mm, so not much
smaller. The
> price is higher for the bigger part, but if you can tolerate
> that, I doubt the small increase in size would prevent you
> from using it.
The price is comparable to an ATtiny48, so that's not going to
knock it out of the running. I think the QFN part probably
would fit. Those are just so not-fun to work with. Could be
worse, could be BGA...
--
Grant Edwards grante Yow! Hey, wait
at a minute!! I want a
visi.com divorce!! ... you're
not
Clint Eastwood!!
Reply by Aaron Greer●October 10, 20072007-10-10
Let's keep this in the list if we can.
I think the OP wants to have both SPI and UART at the same time.
Using the USI won't get him that. Maybe a combo of USI and SW bit bash
would though.
----- "Colin Garlick" wrote: > It's very easy to bit-bash SPI. Particularly if
you are Master.
> Also TimerA is very good at a cycle-accurate UART. So you could use
> F2011,
> and have both SPI & UART with S/w trickery ~300bytes of code (NB This
> is
> NOT
> a CPU cycle timed S/w-UART), but the USI on F20x2 is probably an
> easier
> reach.
>
> Colin,
>
> -----Original Message-----
> From: m... [mailto:m...] On
> Behalf
> Of Microbit
> Sent: 10 October 2007 21:45
> To: m...
> Subject: RE: [msp430] Small msp430 part w/ UART + SPI?
>
> Hi Grant,
>
> AFAIK you have to turn to the bigger buggers because SPI is treated as
> a
> USART, unless I've missed some newer part. But I guess you already
> knew
> that / were afraid of that :-) I guess that's where little buggers
> like
> the AVR are good, they always come with SPI HW regardless of other
> periphs.
>
> Best Regards,
> Kris
>
> -----Original Message-----
> From: m... [mailto:m...] On
> Behalf
> Of Grant Edwards
> Sent: Thursday, 11 October 2007 6:28 AM
> To: m...
> Subject: [msp430] Small msp430 part w/ UART + SPI?
>
> I'm trying to find a small MSP430 part that has both a UART and SPI
> hardware (1 each). I need 2KB of flash and 256B of RAM and about 5
> I/O
> lines (in addition to the UART/SPI). Small size is important.
>
> I've been fighting with the the part selector web page for a while
> and
> haven't been able to find such a part. But, it doesn't seem
possible
> to
> specify 1 SPI and 1 UART, so I may have missed something.
>
> Is anybody aware of a small part with both a UART and an SPI
> interface?
>
> --
> Grant Edwards grante Yow! I'm encased
> in
> the
> at lining of a pure
> pork
> visi.com sausage!!
>
>
>
Reply by Microbit●October 10, 20072007-10-10
Hi Grant,
AFAIK you have to turn to the bigger buggers because SPI is treated as a USART,
unless I've missed
some newer part. But I guess you already knew that / were afraid of that :-)
I guess that's where little buggers like the AVR are good, they always come
with SPI HW
regardless of other periphs.
Best Regards,
Kris
-----Original Message-----
From: m... [mailto:m...] On Behalf Of Grant Edwards
Sent: Thursday, 11 October 2007 6:28 AM
To: m...
Subject: [msp430] Small msp430 part w/ UART + SPI?
I'm trying to find a small MSP430 part that has both a UART and
SPI hardware (1 each). I need 2KB of flash and 256B of RAM and
about 5 I/O lines (in addition to the UART/SPI). Small size is
important.
I've been fighting with the the part selector web page for a
while and haven't been able to find such a part. But, it
doesn't seem possible to specify 1 SPI and 1 UART, so I may
have missed something.
Is anybody aware of a small part with both a UART and an SPI
interface?
--
Grant Edwards grante Yow! I'm encased in
the
at lining of a pure pork
visi.com sausage!!
