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Old 2nd February 2013, 01:53 PM   #421
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At this point I'm not going to pretend I'm picky! Just save some boards for me..
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Old 2nd February 2013, 04:38 PM   #422
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Quote:
Originally Posted by qusp View Post
smallest size though, that would be the LT3032
Yeah, that's a rocking little part. Did you have any trouble with the DAPs shorting while soldering it? I keep thinking about using it but haven't quite found a board that wants it yet.

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Originally Posted by mhelin View Post
Anyway if someone could desing a board with enough TPS7A4700 chips plus single TPS7A3301 and could order the board with the QNF parts soldered and organize a group buy for it I would order couple of boards.
Make sure it has remote sense, otherwise it's probably not going to deliver datasheet performance from the regulators. If one assumes something like a 150mA digital load for SPDIF recieve, Cortex M4, and the digital side of the DAC that means about 100mA want to return through the grounds of the Vcc and Vee regulators since they're in parallel with the Vdd regulator. Exactly what happens depends on supply filtering and parasitics, but for a fairly good layout and filtering I generally sim a millivolt or so of ripple at the regulator output. This defeats a low noise regulator with local sense as the ground topology forces load regulation to be a couple orders of magnitude worse than the noise.

The 4700 formally supports remote sense via its remote pin but the 3001, 3301, and 4901 do not. This is actually more of a problem for the 4700 as it means interesting things have to be done with the ground of the noise reduction cap to implement differential sense (the datasheet connection of the sense pin in figure 24 is single ended, which only works well if ground bounce is significantly less than the regulator's noise). For the other regulators differential sense is simpler---point of load Vdd/Vcc/Vee and ground taps can be brought back to a voltage divider on the regulator board. I am not, however, entirely sure I trust all this not to oscillate. But it's my suspicion remote sense would tend to mitigate the problem as the regulators will be less prone to servoing each other's grounds, reducing low level oscillation.

It would be interesting to see qusp's schematic for how all this is going to work with the regulators floating.

Last edited by twest820; 2nd February 2013 at 04:44 PM.
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Old 5th March 2013, 09:47 AM   #423
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Hi,

I have read your comments about the I2S Communication to the peripheral device. I am beginner in this field and i am thinking if u can help me with Infineon XMC4500 Relax kit spi communication to Peripheral device(9301 controller). I am not able to receive the data from the 9301 controller and i am even not sure that data has been transmitted to the 9301 controller.

Please educate me with the spi communication (transmission and reception) of the infineon xmc4500 relax kit. It will be very helpful if u can provide some sample program and configurations for the kit.

Thanks
Regards
Kamal Negi
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Old 6th March 2013, 07:52 AM   #424
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Quote:
Originally Posted by kamalnegi View Post
Hi,

I have read your comments about the I2S Communication to the peripheral device. I am beginner in this field and i am thinking if u can help me with Infineon XMC4500 Relax kit spi communication to Peripheral device(9301 controller). I am not able to receive the data from the 9301 controller and i am even not sure that data has been transmitted to the 9301 controller.

Please educate me with the spi communication (transmission and reception) of the infineon xmc4500 relax kit. It will be very helpful if u can provide some sample program and configurations for the kit.

Thanks
Regards
Kamal Negi
Haven't got the kit but I would tell you use DAVE and it will generate you enough SPI code. Buy some logic analyzer or scope and watch that you get all clocks and data in and out. Well obviously you should also learn to use the debugger..
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Old 14th April 2013, 01:43 PM   #425
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Default Kudos to Freescale

I think this has to be the first family of Cortex M4s with jellybean pricing - Mouser's showing it at $1.62 in 100s (although no stock currently).

MK10DN32VLF5 Freescale Semiconductor | Mouser

Whilst the Flash memory isn't zero wait state it is equipped with 16k of SRAM, unheard of at this price-point, so probably code can run out of SRAM with no wait states at 50MHz. There's one full duplex I2S port with full buffering and the individual bit clocks on send and receive mean it can be used as an oversampling filter (for example).
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Old 14th April 2013, 05:26 PM   #426
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Quote:
Originally Posted by abraxalito View Post
Cortex M4s - Mouser's showing it at $1.62 in 100s.
Whilst the Flash memory isn't zero wait state it is equipped with 16k of SRAM, unheard of at this price-point, so probably code can run out of SRAM with no wait states at 50 MHz. There's one full duplex I2S port with full buffering and the individual bit clocks on send and receive mean it can be used as an oversampling filter (for example).
With such a low price, one could try one M4 per speaker driver. A three-way active loudspeaker would contain three M4s, each receiving the full audio from I2S, individually filtering the signal, implementing a Power DAC using PWM at 250 kHz followed by a Class-D bridge using N-MOSFETs with bootstrapping for the upper arm. Power supply something like 19V unipolar, for using one or more 90 Watt laptop power supplies. How would I adjust the PWM dead time, for controlling the quiescent current? How would I control the listening volume? Time to get a Sony TA-N88 service manual dating back from 1976. Now that we are in 2013, are there recommendable ICs to be used, for such purpose?
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Old 27th April 2013, 01:17 AM   #427
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NXP just announced this new stand-alone debug board for $20 :

NXP Extends Links to LPCXpresso Ecosystem with LPC-Link 2 :: NXP Semiconductors

I'm puzzled because this looks to be something that would replace a J-Link adapter and at a much lower price, so I must be missing something... Its using an LPC4300 family chip so looks to be the cheapest board to date using this chip - could it even be commandeered as a dev board in its own right?
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Old 27th April 2013, 05:31 AM   #428
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Indeed, not at all a bad price for an LPC4357FET256. I suspect NXP/Code Red found a need to be competitive with the ULink2 clones one can get for <$20 for the Keil toolchain. Given NXP stuck analog and digital expansion headers on the board it's presumably intended for dev board as well as debug use. From what Code Red says I'd check back for further developments in a month or two; NXP may be holding off on releasing the pinouts and such until LPCXpresso can drive the board.

What's perhaps more interesting is the improved dual core support in LPCXpresso 5.2.2. Unfortunately the support wiki permissions aren't allowing access to the multi-core project page at the moment. Yay Code Red.
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Old 27th April 2013, 11:44 PM   #429
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Quote:
Originally Posted by abraxalito View Post
NXP just announced this new stand-alone debug board for $20
I must be very tired, and/or completely out of order. Having seen this PCB full of SMDs, realizing how much money NXP must be losing when producing one, realizing the difficulty of producing one myself, I just asked myself why semiconductor companies don't produce microcontrollers that you can embed on a board made by a 3D printer, with all conducting paths and resistors made in just-in-time by the 3D printer. Only a voltage regulator IC and a few capacitors would be needed, that's all. There is a fairly good probability that somebody tried this with Arduino.
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Old 28th April 2013, 12:29 AM   #430
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Quote:
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I must be very tired, and/or completely out of order. Having seen this PCB full of SMDs, realizing how much money NXP must be losing when producing one..
Its marketing material. RS lost a lot of money giving its catalogues away for free too - hasn't hurt the overall bottom line as far as I can see. NXP understands this and is pricing accordingly - plenty of other chip manufacturers do not get it and price their boards/software with normal margins. For example only the other day I looked at the pricing of ADI's support materials for its SHARC...
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