Cheap, small quad UART needed

Started by Meindert Sprang March 15, 2007
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


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
On Thu, 15 Mar 2007 11:29:38 +0100, "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 >
A small microcontroller would do it, using soft UARTs. Something like an ATMega48. 3 UARTS at 38K4 is probably just about doable at max clock rate with careful coding. Or Two Philips LPC2101's ( 2 HW uarts each) , or one ( 2 HW + 2 SW UARTS). Note that creative use of the SSP port can provide an additional hardware TX UART
"Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> writes:
> 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.
The Renesas M32C cpu family has five uarts per chip, each of which can be configured in one of six communications modes, one of which might be usable as an SPI port. The chip is kinda big, though - 100 pin tqfp, and starts at $23 at digikey. The r8c family is a 20-SSOP at $4 for two uarts plus i2c each.
"DJ Delorie" <dj@delorie.com> wrote in message
news:xnfy865uin.fsf@delorie.com...
> The Renesas M32C cpu family has five uarts per chip, each of which can > be configured in one of six communications modes, one of which might > be usable as an SPI port. The chip is kinda big, though - 100 pin > tqfp, and starts at $23 at digikey.
That is indeed not what I was looking for :-) My ideal UART looks like 20 pins max, maybe a 32 pin TQFP for $5 max. Meindert
<kkkisok@operamail.com> wrote in message
news:etbhfu0om2@enews4.newsguy.com...
> > http://www.nxp.com/products/interface_control/i2c_bridge/index.html
Looks like an interesting candidate, still a lot of surplus pins/signals I don't want/need. Thanks, Meindert
"Mike Harrison" <mike@whitewing.co.uk> wrote in message
news:rfjiv2tbt31urqla8nol0e717ul2lma62s@4ax.com...
> A small microcontroller would do it, using soft UARTs. > Something like an ATMega48. 3 UARTS at 38K4 is probably just about doable
at max clock rate with
> careful coding.
> Or Two Philips LPC2101's ( 2 HW uarts each) , or one ( 2 HW + 2 SW UARTS).
Thought about that too. I'll investigate that more. Thanks, Meindert
On 15 Mar 2007 12:41:36 -0400, DJ Delorie <dj@delorie.com> wrote:

> >"Meindert Sprang" <ms@NOJUNKcustomORSPAMware.nl> writes: >> 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. > >The Renesas M32C cpu family has five uarts per chip, each of which can >be configured in one of six communications modes, one of which might >be usable as an SPI port. The chip is kinda big, though - 100 pin >tqfp, and starts at $23 at digikey. > >The r8c family is a 20-SSOP at $4 for two uarts plus i2c each.
LPC2101 gives 2 UARTS for about $2
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.
Renesas microcontrollers tend to have many UARTS. Check the medium models from M16C family.
On Mar 15, 2:35 pm, Grzegorz Mazur <easy2f...@the.net> wrote:
> 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. > > Renesas microcontrollers tend to have many UARTS. Check the medium > models from M16C family.
LPC2300 from NXP have 4 UARTs, LPC3180 has 7 UARTs, STR910 has 4 UARTS