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i2c bus scan #5

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theedge456 opened this issue Nov 14, 2020 · 9 comments
Closed

i2c bus scan #5

theedge456 opened this issue Nov 14, 2020 · 9 comments
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question Further information is requested

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@theedge456
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Hello,
First, thanks for making this API available. It helped a lot.
I have an old DVB-T dongle derived from the FX2LP connected to an i2c device.
To know what address it is using, I'm using the following code:

#include <fx2i2c.h>
//#include <fx2regs.h>
#include <fx2lib.h>
//#include <stdio.h>

// Scratchpad is from 0xe000 to 0xe1fff (cf TRM sec 5.3 / EZ USB FX2LP p11)

int main() {

  uint8_t i;
 bool r;
 for (i=0;i<128;i++) {
     r=i2c_start(i);
     if (r)
       scratch[i]=i;
     else
       scratch[i]=0x00;
     i2c_stop();
   }
 while (1);
}

The problem is that the dump shows 00 for every element.
Any hint ?

--
Fabien
@whitequark whitequark added the question Further information is requested label Nov 14, 2020
@whitequark
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Can you test this with a known good I2C chip, like a 24C02 or similar generic EEPROM?

@theedge456
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theedge456 commented Nov 15, 2020 via email

@theedge456
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theedge456 commented Nov 16, 2020 via email

@whitequark
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Ok. What if you do the same on your original dongle? Also, you might want to scan write addresses only (i<128, i2c_start(i<<1)). If you scan read address you need to read a dummy byte afterwards.

@theedge456
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theedge456 commented Nov 16, 2020 via email

@whitequark
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Yes, that seems to imply that the dongle has loaded its firmware from a EEPROM at the unshifted address 0b1010001.

@theedge456
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theedge456 commented Nov 17, 2020 via email

@whitequark
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Sure. I don't see what that has to do with libfx2 though.

@theedge456
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You're right

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