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thwill

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Joined: 16/09/2019
Location: United Kingdom
Posts: 4311

Posted: 02:35pm 29 Nov 2021

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Hi folks,

I'm reasonably certain that I had @Mixtel90's PicoMite backpack (with touch untested) working last week, but this morning following a firmware update (b8) I'm experiencing some grief; I have tried downgrading the PicoMite to 5.07.00 but it hasn't helped.

The symptoms are that if the PicoMite and backpack are powered up (from laptop or Pi via USB - has always been fine before) with all pins connected (Screen, Touch and SD) then I can't read the SD card: "Error: SD Card not found. However if I power up without the 5 touch pins connected, or disconnect the 5 touch pins then I can read the SD card, even if I subsequently reconnect the touch pins.

I have reflowed all the solder joints on the connectors between backpack and screen.

Any ideas ?

Best wishes,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

thwill

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Joined: 16/09/2019
Location: United Kingdom
Posts: 4311

Posted: 02:38pm 29 Nov 2021

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LOL ... 30 seconds later the light bulb comes on, you have to do "OPTION TOUCH GP14, GP15" even if you aren't interested in touch.

God damn, how much time have I wasted this morning

.

In good news the PicoMite is very robust as I've been giving it some extreme grief and plugging/unplugging pins and power with complete abandon as I've tried to beat it into submission.

Best wishes,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 05:04pm 29 Nov 2021

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But just think of all the wonderful things that you've learned. :)

I wonder why you have to configure touch?

I really like the PicoMite. :)

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

thwill

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Joined: 16/09/2019
Location: United Kingdom
Posts: 4311

Posted: 05:44pm 29 Nov 2021

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Mixtel90 said But just think of all the wonderful things that you've learned. :)

Patience and frustration in equal measure. Everytime I wired the PicoMite to the backpack with jumpers everything worked, everytime I directly attached them it didn't. Of course when I was wiring it up with jumpers I wasn't attaching the touch pins because I wasn't interested in them, it took a long time for the first bulb to come on and realise the touch pins were the problem, and then there was another long delay for the second bulb to light and suggest I might need to set OPTION TOUCH whether I was interested or not.

Thanks again for the Backpack PCBs - I think

.

Best wishes,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10310

Posted: 05:52pm 29 Nov 2021

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Page 43 of the PicoMite manual

Quote Care must be taken when the SPI port is shared between a number of devices (SD card, touch, etc). In this case all
the Chip Select signals must configured in MMBasic or alternatively disabled by a permanent connection to 3.3V.
If this is not done any floating Chip Select signal lines will cause the wrong controller to respond to commands on
the SPI bus.

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 06:03pm 29 Nov 2021

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Ah, yes. On the backpack the touch pins are hard-wired to the PicoMite. If you don't want touch enabled you could just set T_CS (GP14) high at the beginning of your program instead of setting the touch option.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

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