Hardware » CANBuz

h1. Eval

CANDis is quite silent.

CANBuz probably will have same issues. Need to test capacitors.

F=As/V

qalc 0,000022*3 = 0,000066 = 0,066mAs

Ich hab doch noch grosse 

Is it the power regulator/LDO? What did i solder?

h2. Parts

* LM386; "DS":https://www.ti.com/lit/ds/symlink/lm386.pdf ; page 10

* LM4861 M; 1,39€

** can be driven @5V; not sure if V+ has to be 3v/2 or 5v/2 ?

** Shutdown: power output off on logic high

h2. Amp

"lm4871":https://www.ti.com/lit/ds/symlink/lm4871.pdf

h2. MCU

* STM32F042G4U6; UFQFPN28; 16KB; hab ich noch 17

* Get rid of an STM32F072 in order to have DAC?

* STM32G431KBU6

** SAI; FPU

** 5,87€

* STM32F072CBT6

** LQFP-48

** 2,40 €

* STM32F103CBT6

** 2,12 €

* STM32F303K8 -C6U6A-

** FPU; Cortex M4; 72MHz

** When name is really correct, its a  LQFP48 with 32KB flash

** No, it's LQFP32 with 64KB flash

h2. DAC

* Maybe later; SAI would be more interesting. DAC for testing DMA.

* 44,100 Hz

* Would require SPI flash for recorded sound

* Adjustable volume

* Solderbridge for fallback

h2. Replay

Would need 20KHz;

have 12 Kbytes RAM;

2KB plays 1/20secs

Stereo gets tricky. There is only 1 SPI. Would need to couple DAC outputs. Maybe test this later.

h2. Flash

DAC-DMA already works for sinewave (copied due to speed). So FLash might be cool for sound samples.

CD: 44100 samples / sec; 

44100*2*2 = 176'400 Bytes / s; Flash readout has to be a little bit faster for the overhead.

1MB would play around 6 seconds. 2MB / 16Mbit would be ok.

32Mb/4MB available for 1,94€; 100Mhz

STM32F303 has max SPI rate 18Mbits/s or 2,25MB/s wide range voltage; 24Mb/s or 3MBytes/s normal range

MX25L3233FM1I-08G is 83 cents; supports QIO

Irgendwas muesstte ich eh noch haben, hab mal groesser eingekauft.

h2. USB

USB would be nice for writing sound samples to flash. But this might be a nice candidate for writing flash images over CAN.

Although it might take very long time.

h2. Flash via CAN

A CAN frame has 108 bits. 500khz/108 = 4629 Msg/sec = 18KB/s

32MB needs 1820 seconds, 30 minutes. Flashing sector by sector with retrys is needed.

A sektor has 4K

h2. Flashing light

* Golden dragon; Durchlassstrom: 20 – 1000 mA; Durchlassspannung: 2,7 – 3,7 V (?, maximal werte?

* V_F 400 mA: Typisch 2.20