Adventures with I2C & Minerva Mk2

[t0nyt]

Exactly. I laid out the pseudo code for a scanner near the start of this thread

I thought you had, but damned if I can find it

[t0nyt]

Ok, that's worked a treat thanks

Sorry for being so thick, Many thanks all

New code

Code: Select all

100 WHEN ERRor
110    f=0
120    CONTINUE
130 END WHEN
140 PRINT "SCAN STARTING"
150 c$=CHR$(164) & CHR$(255)
160 FOR x = 0 TO 127
170    f=1
180    r$=I2C_IO(c$,0,x,0)
190    IF f=1 THEN PRINT "Device Found at " & HEX$(x,8) & " (" & HEX$(x*2,8) & ")"
200 NEXT x
210 PRINT "SCAN COMPLETE"

Sample output

[t0nyt]

The scanner has thrown up an issue with the AT24C256

It shows as both &54(&A8) AND &5C(&B8), confirmed as when unplugged both devices vanish

&54(&A8) works fine with both test programs

&5C(&B8) corrupts the end of the "page test" text
I thought maybe it was writing to Minerva, but on checking settings they hadn't been corrupted

Reading the data sheet I can't work out why this is happening

Any thoughts on how I could troubleshoot this please?

Many thanks
Tony

[XorA]

No idea on your problem!

But not all i2c addresses are valid so you can speed up your loop by skipping the invalid ones!

https://www.i2c-bus.org/addressing/

[t0nyt]

No idea on your problem!

But not all i2c addresses are valid so you can speed up your loop by skipping the invalid ones!

https://www.i2c-bus.org/addressing/

Thanks for the link XorA, will have a read thru thanks

The current scan only takes about 1 second (on SGC)

[t0nyt]

The scanner has thrown up an issue with the AT24C256

It shows as both &54(&A8) AND &5C(&B8), confirmed as when unplugged both devices vanish

&54(&A8) works fine with both test programs

&5C(&B8) corrupts the end of the "page test" text
I thought maybe it was writing to Minerva, but on checking settings they hadn't been corrupted

Reading the data sheet I can't work out why this is happening

Any thoughts on how I could troubleshoot this please?

Many thanks
Tony

I bought a 5 pack of these and I just tried the other 4 and even using the correct address they don't work properly

The fact that 1 seems to work, on proper address, makes me think these are a cheap knock off

Will order another from somewhere more reputable to test

[XorA]

I think we should get you a "Member of the I2C Club" badge now

[Pr0f]

The scanner has thrown up an issue with the AT24C256

It shows as both &54(&A8) AND &5C(&B8), confirmed as when unplugged both devices vanish

&54(&A8) works fine with both test programs

&5C(&B8) corrupts the end of the "page test" text
I thought maybe it was writing to Minerva, but on checking settings they hadn't been corrupted

Reading the data sheet I can't work out why this is happening

Any thoughts on how I could troubleshoot this please?

Many thanks
Tony

What have you got the 3 address lines tied to on these NVRAM's ? Don't leave them 'flapping' or unconnected. You need to set at least one of these pins to 5v logic 1, so that you avoid contention with the RTC chip, you may also need to avoid other chips that have clashing addresses.

[t0nyt]

What have you got the 3 address lines tied to on these NVRAM's ? Don't leave them 'flapping' or unconnected. You need to set at least one of these pins to 5v logic 1, so that you avoid contention with the RTC chip, you may also need to avoid other chips that have clashing addresses.

A2 is tied to 5v and A0/A1 tied to ground (to avoid clash with Minerva NVRAM)

No other clashes (and it's the same with just this 1 device attached)

Thanks
Tony

[Pr0f]

Have you got a picture of the chip to see what the label looks like?

You did mention the possibility of them being suspect...