Hi everybody – finally i found time to write some code for the Oggstreamer and i put to work some of the basic functions of the device. I started with the StatusLEDs and the VU-Meter …
There are some news: I switched to the IAR Workbench Kickstarter Version for STM8 because i like the Idea of having an all in on package for Firmware development – And especially when it comes to debugging i find this Software package quite comfortable. The preliminary Sourcecode for the STM8 Firmware got new git-repository, which can be found here. The Kickstarter Version is limited to 8 KB Codesize, which should not be a problem – i expect the firmware to be around 4KB big – the remaining 24KB of flash can be used to store patchfile updateimages for the VS1063
The first thing i implemented on the firmware are the routines for LED – Muxing. We are using one complete PORT (GPIOB) and some controll Lines on GPIOA to drive the LEDs. Timer4 is used to generate a 450 Hz Inerrupt and because we are Muxing 3 different LED-Rows (VU-LEFT, VU-RIGHT and STATUS) – each row gets updated at a 150 Hz Refresh rate. The CPU usage for the muxing is around 0,2 % which is little enough in my eyes.
I also tried to get the VS1063 running – but measuring the Crystal it showed that it is not oscillating – I also remembered that i had some shorts on the supply lines, because at first try the VS1063 was not proper soldered – maybe I killed the VS1063 and i have to replace it now – but this issue definitely needs further investigation.
My best wishes to all of you for the new year. 🙂
Welcome on Board Abatec. This company will do the Pick’N’Place for the first batch of OggStreamer-Devices. Thanks you very much! Check out their promotion video below (it is German):
Abatec is a austria-based company. They do engineering as well as the complete production of devices. Their competences spread over a broad spectrum. Besides that they also have a strong focus in engineering Wellness (Saunas, etcs..) products.
Thanks very much – doing the Pick’N’Place sounds easy but this process takes a lot of work – So this is a really big favor this company is offering to us.
We are also thinking of recording the Pick’N’Place process using a high speed camera – as their machinery is to fast to be to be visible to the naked eye 🙂
“Doing an OpenHardware-Design is like running a Teardown, while your device is not even built!” – came to my mind when i took the first pictures of the coming OggStreamer.
With the great help of Johann, we now have a housing. We got some minor flaws with the mechanics but nothing serious – in overall i am very happy with the case.
Yesterday I received two Emails which really encouraged me that doing a Design the OpenHardware-Way is a great thing to do.
The first one was a Mail from the Wyolum-Team – they just awarded Grants to the OpenHardware-Community. I was kind of sceptical if the OggStreamer could score in this setting, because there were really, really good projects on their List. I want to say that the Wyolum-Team are really sympathetic folks – they just decided to give out more grants than the originally intended 😉 – Thank you very much. They are now supporting this Project with 250 USD. This means for this Project that we are able to give away another Device to an interested Developer.
The other Mail was from A1bert – who commented on the last Blog entry – that one should be aware to not over-design things. He pointed out that the VS1063 has a decent Power Supply Noise Rejection for its Analogaudio-Voltage. So an aditional LDO as a Filter might be to much of an effort.
I was very happy about his suggestion, because this is a valuable feedback for me – as I am kind of an Analogdesign newbie – these are just the informations we need to reflect on the work we are doing on the OggStreamer.
Thank You very much Wyolum-Team and a1bert – you made my day 🙂
And there are more great news. My former employer Abatec also agreed to support this project by doing the pick’n’place for the first batch of devices. This is really great because, soldering the device by hand takes almost half a day.
Yesterday late in the night i ran a Spice Simulation of the Filters for Analog Voltage and it showed that they are not suited to block noise in the audible spectrum (10Hz-20kHz). One option to design them better is the usage of low-noise LDOs with a high input rejection to efficiently “filter” the audio supply-rails. I am thinking of a device like the LP3982.
Simulation was done using the freely-available LTSpice-Software under WINE. Fortunately the used ferrite-beads from Würth are included in its standard library.
Simulations shows that the filter is just blocking Signals well over 100kHz – all the audible noise will pass this filter rather unimpressed. Also tweaking the L is not really helpful.
Summing up all the issues on the PCB – I decided to run a redesign of the PCB now – before we start the production of the 10pcs. batch. I think this is the smarter way to do it. Because i don’t know what will happen after the first 10pcs. are produced – The thought is something like that: If we don’t do it know, we probably will never do the redesign …
this weekend I started to solder the first pcb by hand – a moment of truth – here is a list of what happened:
- LD1117 LDOs need 1V voltage difference in order to work proper – we need to replace our serial diode (D4) with a schottky type – or a 0 Ohm bridge
- The the numbering of the LED-pcb-connector is the other way around – the connector has to be mounted upside-down and the cable is twisted now.
- the DC Plug is connected the wrong way – some dremel is needed to cut the traces on the PCB and it is wired by hand
- A pull-up Resistor for the Reset-Line on STM8 is missing (10 kOhm)
- A pull-down Resistor is needed for GPIO0 on the VS1063 (100 kOhm)
- Not verified yet – but I think the Filters for the analog Voltage-Supply (OPA, Vdd_analog on VS1063) need a redesign as well.
In general the PCB would need a redesign! – For our first batch I will do the modifications by hand. The PCB needs a redesign!
Some good news: The LED Multiplexing circuit is working already.
The PCBs from WEdirekt arrived today! *rataplan* And that’s what they look like:
Sounds like soldering-weekend. 😉