Hi, Jean Delvare <khali at linux-fr.org> writes: > Partly right. Actually, most SMBus controllers work the following way: > you program a number of registers (typically SMBus transaction type, > target chip address, target register address or command, and the data to > send in the case of a write transaction), So, with one transaction, can I write an arbitrary number of bytes to the device, and then, in the same transaction, can I read one (or no, or with some controllers, more than one) byte(s) back? >> But wait, even then does the controller really know anything about >> I^2C commands? How would it differentiate between, say, 8-bit and >> 16-bit reads? Or is it just an 8-bit EEPROM bus? > > No, it is still physically a 2-wire serial bus. Sure, I rather meant "a bus _for_ I^2C EEPROMs which use 8-bit (+3) addressing". > The limitation is due to > the fast that the SMBus controller knows of a limited number of > transactions, such as Send Byte, Read Byte, Read Word etc. If the SMBus > controller doesn't know of the SMBus command you want to use (in my > case, I2C block read), then there is no way to do it, because we have no > direct control over the serial line. Interesting. Still, that limits it to 8-bit-addressable EEPROMs. Are such things documented somewhere on the net (some datasheet maybe)? -- Krzysztof Halasa
