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circuit
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Joined: 10/01/2016
Location: United Kingdom
Posts: 293

Posted: 07:32pm 27 Jun 2022

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I have connected successfully five 7" SSD1963 displays on two Micromite Plus, two Armmite F4s and a PicoMite respectively. All with keyboards configured and SD cards working fine.

I have now built a new 144 PIN MicroMite eXtreme and the display works okay (stunningly fast..), the keyboard also, but I cannot get the SD card on the display to read. (The SD card works fine on other machines).

I have connected the SSD1963 SD card as follows;

SD-DIN TO PIN 105
SD-DO TO PIN 95
SD-CS TO PIN 93
SD-CLK TO PIN 14

I have then declared; OPTION SDCARD 93

The card is not found.

Any help please?

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 8304

Posted: 07:56pm 27 Jun 2022

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To use OPTION SDCARD 93 (which only specifies the CS line) you have to set up system SPI first. I assume you did that?

Mick

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

circuit
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Joined: 10/01/2016
Location: United Kingdom
Posts: 293

Posted: 08:37pm 27 Jun 2022

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Mixtel90 said To use OPTION SDCARD 93 (which only specifies the CS line) you have to set up system SPI first. I assume you did that?

No I have not. I am not aware of that need with the MicroMite eXtreme (no mention in the manual). I am aware of this procedure for the PicoMite. I find no reference to OPTION SYSTEM SPI for the eXtreme, only the PicoMite.

The manual for the eXtreme states;

OPTION SDCARD CSPIN [,CDPIN] [,WPPIN] [,SPIno]

The SPI channel used for the SD Card (if configured) defaults to the second channel (SPI2) however this can be changed by appending the SPI channel number to the end of the OPTION SDCARD.

The pins I have connected to correspond to SPI2 on the 144 pin chip -the default.

Can you clarify this dilemma?

Mixtel90

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Joined: 05/10/2019
Location: United Kingdom
Posts: 8304

Posted: 08:59pm 27 Jun 2022

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I doubt it. :(

I've had no dealings with the eXtreme, unfortunately. I forgot that the PicoMite is different to the others.

I wondered if the SSD1963 had series resistors in the data lines, but mine doesn't appear to. In any case, you've had it working on other platforms so it's unlikely to be anything like that.

All I can think of is the power supply. It might be worth temporarily connecting an electrolytic capacitor of 10-100uF across the SD socket pins. It's not usually a problem when reading though. Are you getting enough voltage at the SD card?

Mick

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

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 10627

Posted: 09:43pm 27 Jun 2022

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SD_DIN and SD-DO are the wrong way round

circuit
Senior Member

Joined: 10/01/2016
Location: United Kingdom
Posts: 293

Posted: 09:12am 28 Jun 2022

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matherp said SD_DIN and SD-DO are the wrong way round

Such a schoolboy error! My embarrassment, but thank you Peter for your rapid intervention. All working fine now.

For me, the 144-pin eXtreme chip remains at the pinnacle of the Micromite family. What I miss in the Pico is the LIBRARY (as well as all the extra pins...).

Fortunately, I stocked up on MZ and MX chips when I saw that a chip shortage was on the horizon; I grabbed the last five MZ 144 pin chips at RS. Projects ahead for all of them!

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