15/08/2020

This is still very much work in progress.

 

I've confirmed my primary choice of display, the Riverdi RVT43ALBFWN00, available from Mouser and RS.

It has an SPI interface over a 20 way FPC and uses a Bridgetek controller chip. This is fairly smart and reasonably

well documented chip and very much mitigates the slowness of controlling a hi res display over SPI. It costs about £27.

 

Here's a picture - of the important side !

 

 

The plan is that the display will bolt onto the main pcb (on the non component side) and connect via a short flat cable.

 

I've wasted a lot of today trying to get to grips with the Espressif ESP32 WiFi and Bluetooth chip and it's modules. When I first

suggested using this part I mention that there is a lot of community support for it. It's more a case of a lot of community talk about it !

Precious few schematics that inspire confidence.

The best article I found about getting it to work with AT commands was far too scary:- don't use the latest version of the tools, compile the code

again because it won't work if you use the binary, install and hack some kind of boot config tool thing ... and on and on ! How can this thing

possibly claim any kind of certification ?

 

I've used a Microchip module, it only does Bluetooth and it costs twice as much, but you connect it, configure it (without re-designing the tools) and it works.

 

We could use that,  but I'm now thinking of just providing a header with serial port, six uncommitted IO lines and 3.3V power (peak current 1A).

 

If anyone has a certified module in mind, that they have used and can link me to a schematic of it interfaced to micro ( that is known to work),

I could be persuaded.

 

I've got a preliminary processor pin allocation, I end up with about 25 IO pins free, so certainly no need for more than the 100 pin package.

 

 

 

I've also completed my battery testing programme.

I bought a pair of claimed to be 7.4V 8.8Ah Sony compatible batteries from Amazon - very cheap at £41

for both batteries and the dual charger. The charger is slow(since it's USB powered but it works OK.

I did 10 successive run down tests and the results are surprisingly good. Not quite up to spec but little sign

of early degradation. One battery has about 4% more capacity than the other -  not  a big deal.

 

 

if anyone has any ideas re the BlueTooth.WiFi I'd really like to hear about it.

 

(BTW - I forgot to tag the last blog about the ADC properly.)

 

MK