Reply by March 27, 20072007-03-27
"Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> writes:
> The only drawback of that is that I need an ISP facility (connector > or pads) for every micro. It would have been nice if Atmel has made > the ISP system daisy-chainable.
My latest board has five ISP chips. Most of the lines can be connected together; I only needed separate lines from the main cpu for each reset, and a mux for the Tx lines. So, they all got the programming data, but only one was paying attention.
Reply by Jim Granville March 27, 20072007-03-27
Meindert Sprang wrote:
> Thank you all for your comments. > > My ideal solution would still be a small FPGA but as mentioned, there aren't > any with sufficent cells for 4 uarts without having 100+ pins. So I'll go > for the small micro solution. The only drawback of that is that I need an > ISP facility (connector or pads) for every micro. It would have been nice if > Atmel has made the ISP system daisy-chainable.
We have mentioned the same thing to them :) - but you can share some of the pins, to reduce the total pin cost, and you can also ISP the newest AT89LPxx series, over the 2 wire OCD, as an alternative. -jg
Reply by Meindert Sprang March 27, 20072007-03-27
Thank you all for your comments.

My ideal solution would still be a small FPGA but as mentioned, there aren't
any with sufficent cells for 4 uarts without having 100+ pins. So I'll go
for the small micro solution. The only drawback of that is that I need an
ISP facility (connector or pads) for every micro. It would have been nice if
Atmel has made the ISP system daisy-chainable.

Meindert


Reply by Ulf Samuelsson March 20, 20072007-03-20
"-jg" <Jim.Granville@gmail.com> skrev i meddelandet
news:1174101948.586680.170880@e1g2000hsg.googlegroups.com...
> > Meindert Sprang wrote: >> Hi Guru's >> >> I need a quad UART chip with only RXD and TXD per channel, no handshake >> required, preferable communicating with my CPU through an SPI port. >> Baudrates in the range of 4800 to 38400 baud. Oh, and it needs to be >> cheap. >> >> I am thinking about a small controller but most only have two UARTS and >> doing four in software at 38400 seems quite a challenge to me. So maybe s >> small FPGA/CPLD solution would be in order. But most of all, it needs to >> be >> simple, cheap and small footprint. >> >> All suggestions are welcome. > > Have you looked at Philips / Exar ? > Don't forget to include 2 x Dualchannel uC as they may still be > cheaper than > a Quad solution. > If this has to be 'no shortcuts' with full duplex, full buffering, and > handshake, then > it's going to push a single uC, and for CPLDs you'll also find it hard > to source one > that is going to compete with 2 cheap uC, in $ and PCB area. > Something like the AT89LP216 from Atmel, at ~90c/10K, will do 1 Chan > in HW, and > probably 1 more in SW, so that's ~ $2 - the new SiLabs C8051T600 has > i2c, no SPI, > but thats getting under 50c for a single channel. > most likely CPLD,resource wise, would be the Lattice MachXO,but they > start at > 100 pins.. > -jg >
And still an AT91SAM7S161 in a 9 x 9 mm seems superior. 3 UARTs + H/W Support for full duplex UART, all w DMA support and SPI in a 9 x 9 mm package. -- Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB
Reply by Ulf Samuelsson March 17, 20072007-03-17
>>>><snip> >>>>AT91SAM7S321 in QFN-64 (AT91SAM7S161 when available)? >>> >>> I seem to recall this from Meindert, earlier: "My ideal UART looks >>> like 20 pins max, maybe a 32 pin TQFP for $5 max." >>> ^^^^^^^^^^^ ^^^^^ >>> >>> Jon >> >>Both are 9 x 9 mm, whats the big deal ?? > > Both parts you recommended, I suppose. The "maybe a 32 pin TQFP" is > 7x7 mm, isn't it? >
The actual package yes, but the pad ring is 9 x 9 mm in both cases. Admittedly, the layout of the 32 pin TQFP is more tight, since you cannot have vias under a QFN package. -- Best Regards Ulf Samuelsson
Reply by Jonathan Kirwan March 17, 20072007-03-17
On Sat, 17 Mar 2007 16:23:31 +0100, "Ulf Samuelsson"
<ulf@a-t-m-e-l.com> wrote:

>Technical support when I am not available: >AT89 C51 Applications Group: mailto:micro.hotline@nto.atmel.com >AT90 AVR Applications Group: mailto:avr@atmel.com >AT91 ARM Applications Group: mailto:at91support@atmel.com >FPSLIC Application Group: mailto:fpslic@atmel.com Best AVR >link: www.avrfreaks.net >"Jonathan Kirwan" <jkirwan@easystreet.com> skrev i meddelandet >news:4rekv29qok8knpjuue6fl55rcjr9pgg4c1@4ax.com... >> On Fri, 16 Mar 2007 06:20:08 +0100, "Ulf Samuelsson" >> <ulf@a-t-m-e-l.com> wrote: >> >>><snip> >>>AT91SAM7S321 in QFN-64 (AT91SAM7S161 when available)? >> >> I seem to recall this from Meindert, earlier: "My ideal UART looks >> like 20 pins max, maybe a 32 pin TQFP for $5 max." >> ^^^^^^^^^^^ ^^^^^ >> >> Jon > >Both are 9 x 9 mm, whats the big deal ??
Both parts you recommended, I suppose. The "maybe a 32 pin TQFP" is 7x7 mm, isn't it? You need to ask Mendert this question, though. I was just remembering his comment.
>It'll do the job, and it is in the price range.
In 100's. I think your proposition is fine, except you didn't point out clearly where it deviated and where I'm sure you already knew it. With the caveat of size and qty included, I wouldn't have said anything at all. I've read Meindert's posts and I know he knows a lot about what he's doing. So I tend to take his boundary criteria with a fair degree of seriousness, as a starting point anyway. Jon
Reply by Ulf Samuelsson March 17, 20072007-03-17

Technical support when I am not available:
AT89 C51 Applications Group: mailto:micro.hotline@nto.atmel.com
AT90 AVR Applications Group: mailto:avr@atmel.com
AT91 ARM Applications Group: mailto:at91support@atmel.com
FPSLIC Application Group: mailto:fpslic@atmel.com Best AVR
link: www.avrfreaks.net
"Jonathan Kirwan" <jkirwan@easystreet.com> skrev i meddelandet 
news:4rekv29qok8knpjuue6fl55rcjr9pgg4c1@4ax.com...
> On Fri, 16 Mar 2007 06:20:08 +0100, "Ulf Samuelsson" > <ulf@a-t-m-e-l.com> wrote: > >><snip> >>AT91SAM7S321 in QFN-64 (AT91SAM7S161 when available)? > > I seem to recall this from Meindert, earlier: "My ideal UART looks > like 20 pins max, maybe a 32 pin TQFP for $5 max." > ^^^^^^^^^^^ ^^^^^ > > Jon
Both are 9 x 9 mm, whats the big deal ?? It'll do the job, and it is in the price range. -- Best Regards Ulf Samuelsson
Reply by -jg March 17, 20072007-03-17
Meindert Sprang wrote:
> Hi Guru's > > I need a quad UART chip with only RXD and TXD per channel, no handshake > required, preferable communicating with my CPU through an SPI port. > Baudrates in the range of 4800 to 38400 baud. Oh, and it needs to be cheap. > > I am thinking about a small controller but most only have two UARTS and > doing four in software at 38400 seems quite a challenge to me. So maybe s > small FPGA/CPLD solution would be in order. But most of all, it needs to be > simple, cheap and small footprint. > > All suggestions are welcome.
Have you looked at Philips / Exar ? Don't forget to include 2 x Dualchannel uC as they may still be cheaper than a Quad solution. If this has to be 'no shortcuts' with full duplex, full buffering, and handshake, then it's going to push a single uC, and for CPLDs you'll also find it hard to source one that is going to compete with 2 cheap uC, in $ and PCB area. Something like the AT89LP216 from Atmel, at ~90c/10K, will do 1 Chan in HW, and probably 1 more in SW, so that's ~ $2 - the new SiLabs C8051T600 has i2c, no SPI, but thats getting under 50c for a single channel. most likely CPLD,resource wise, would be the Lattice MachXO,but they start at 100 pins.. -jg
Reply by rickman March 16, 20072007-03-16
On Mar 15, 6:29 am, "Meindert Sprang" <m...@NOJUNKcustomORSPAMware.nl>
wrote:
> Hi Guru's > > I need a quad UART chip with only RXD and TXD per channel, no handshake > required, preferable communicating with my CPU through an SPI port. > Baudrates in the range of 4800 to 38400 baud. Oh, and it needs to be cheap. > > I am thinking about a small controller but most only have two UARTS and > doing four in software at 38400 seems quite a challenge to me. So maybe s > small FPGA/CPLD solution would be in order. But most of all, it needs to be > simple, cheap and small footprint. > > All suggestions are welcome.
I don't see where you got much discussion on CPLDs. There are any number of CPLDs in small packages. However, they don't typically have as small pin counts as you would like, 20/32 pins. They tend to start around 48 pins for CPLDs, but a 48 pin TQFP is a pretty small device. Most CPLDs will be register limited however. To implement 4 UARTs and an SPI interface, you will need to define a protocol for the SPI interface and it will require most likely a command word to be written for each byte transferred in either direction. I estimate about 24 FFs for the SPI including the state machine (off the top of my head). You will need some 20 FFs per receiver and another 24 per transmitter if you want it double buffered. The baud rate generator can be in the range of 8 to 16 FF. So this totals some 200+ which puts you in a 256 MC CPLD. These tend to be a bit pricey and are typically not available in a small package. So your MCU approach is likely to be the best. There are parts that can do this job easily, but you will need to go with a BGA to even get close to a small package. I have seen FPGA vendors discuss how there is little demand for higher density devices in smaller pin count packages. I often wonder if that is really the case or if it is really just a matter of them wanting to pick the low hanging fruit rather than to compete on lower margin devices. They don't have to sell very many $1000 FPGAs to bring in more profit than the $4 parts. But I know I have had applications for small FPGAs in low pin count packages.
Reply by Roman March 16, 20072007-03-16
kkkisok@operamail.com wrote:
> On 15-Mar-2007, "Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> wrote: > >> Hi Guru's >> >> I need a quad UART chip with only RXD and TXD per channel, no handshake >> required, preferable communicating with my CPU through an SPI port. >> Baudrates in the range of 4800 to 38400 baud. Oh, and it needs to be >> cheap. >> >> I am thinking about a small controller but most only have two UARTS and >> doing four in software at 38400 seems quite a challenge to me. So maybe s >> small FPGA/CPLD solution would be in order. But most of all, it needs to >> be >> simple, cheap and small footprint. >> >> All suggestions are welcome. >> >> Meindert > > http://www.nxp.com/products/interface_control/i2c_bridge/index.html
Realy nice product indeed. This goes for $2.50 for 1 channel and $4 for 2 channel device in single quantity at Digikey. Seems this is exactly what OP is searching for. Thanks for the link.