MCP2200 - expensive piece of junk

[RGV250]

Hi,
Just in case anyone sees this https://uk.rs-online.com/web/p/communication-wireless-development-tools/8252486 and thinks it is a good idea, forget it, it is another uselesss piece of Microchip junk. I was looking for a USB/TTL adaptor and saw this which says it has 8 GPIO pins and 256 bytes EEPROM. I thought that could be useful but it is not until you start reading deeply that the GPIO and EEPROM is only available from the USB side. So in effect it is just a very expensive USB/TTL module.
Also the configuration utility does not show up in the uninstaller so you also clutter your PC up with more junk.

Not a very happy Bob

[JonW]

Bob if you still need an adaptor PM me, and ill send you some I build.  It's based on CP2102 and has USB-C.  Ports out VDD, GND, RX, TX and MCLR that are triggered from RTS to enable bootloader transfers. 
I also have a simple Gui that can control RTS and can send ASCII, DEC or HEX and include EOL characters etc.

[RGV250]

Hi Jon,
I have several adaptors but this one seemed a bit special, it shows 256byte eeprom and 8 gpio and nothing says it cannot be accessed from the UART.
It gets worse, the configuration utility does not run under Windows 10, it gets even worse than that. I have managed to use MPLAB to program the Microstick and was getting to like?? it. I then started to get warnings that I was about to write to an area that is not allowed or something like that. It turns out that if you have the MCP2200 on the USB at the same time MPLAB thinks it is programming the MCP, I have to wonder what the Microchip programmers do, testing is not part of it thats for sure.
 

Bob

[JonW]

Oh see it now.  Expensive clone of the FT232 as you can get access to some GPIO on that, but again it's from the USB side.  You could always do your own version using that dev board I sent you.  CUart1 is connected to the CP2102 and the other UART2 could be true logic level Uart to connect to your dev boards  Then add your own commands for E2 and IO with the Uart2 and transfer data to/from your PC with a custom terminator or other command that sends bytes from UART1 to UART2.

Nice little project and you don't even need a programmer as you can code it all up with the bootloader.   

[tumbleweed]

...and nothing says it cannot be accessed from the UART.

And nothing says it CAN be accessed from the UART either.

If you're using MPLABX v6.10, I'd suggest dropping back to V6.05 (or earlier).
V6.10 removed support for all the pickit3/PKOB3 tools, so you need at least a PK4-based tool/board.
Supposedly this will be fixed in V6.15...

[RGV250]

And nothing says it CAN be accessed from the UART either.

I would say the block diagram does, I am pretty sure the configuration and control registers cannot be accessed by the UART either so if it is not possible then surely the Control block should be drawn differently.

I was using the latest MPLAB X which explains why it could not find the starter kit on board. The datasheet does say MPLAB 8.76 or later. It also mentions MPLAB X but nothing to specify what version.

Bob

[RGV250]

Hi Jon,
I forgot to reply, that is a good idea, I was actually thinking of doing it as a TTL/USB adaptor to another device. The main reason is that Microchip went backwards when designing the PIC24, I do not think any have EEPROM on board, the CAN ones do not anyway. Surely the sucessor should always be better than what it is replacing, not doing half a job.
You could argue why not have a seperate EEPROM but as I will have a TTL/USB connected why not use it.

Bob

[Stephen Moss]

And nothing says it CAN be accessed from the UART either.

I would say the block diagram does, I am pretty sure the configuration and control registers cannot be accessed by the UART either so if it is not possible then surely the Control block should be drawn differently.

Well I guess it depends on an individuals interpretation as different people can see things in different ways, personally I would not say it indicates that.
If there was a direct connection shown between the UART & the EEPROM, then I would say you were correct in what you say, however it only shows connections from the UART to the Control unit and so all you can tell for certain from the block diagram is that...
1) The Control block appears to have Tx & Rx connections to both the USB & UART as one may expect, as it appears to essentially be a USB to serial converter and
2) That the Control block also has access to the EEPROM

There is no definitive indication as to whether the USB, UART or both have access to the EEPROM, via the Control block, and if everything has to pass through the Control block I am not sure it could have been drawn in any clearer way except possibly colour coding the data flow arrows to show if they relate to the UART, USB or both.

I am pretty sure the configuration and control registers cannot be accessed by the UART either

Correct, section 1.7 of the data sheet clearly states "The memory locations are accessed for read/write operations via USB host commands.", and section 2.0 clearly states "The MCP2200 is configured by writing special commands using the HID interface." and therefore has to be only under USB control as UARTS do not usually have a HID interface.     

[RGV250]

I am not sure it could have been drawn in any clearer way

Bob