I am really new on this and therefore ask a stupid question.
What is the address of A25L40PT? I have read the data sheet but cannot find it.
Also if you do have pointers to SPI in the web. The Wikipedia one I already found but others would be of interest. Also if there is a book about SPI I would be very interested to know it's ISBN and name.
Also if there is a book about I2C that would be interesting too.
Best Regards Kari
--
PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI -
KEYPADS - ACCESSORIES
http://www.byvac.com (I am just a satisfied customer)
There is no address for this SPI device, it uses the chip select to select it. Some SPI devices have an 'address' field but that is usually to allow a common chip select, however they are not really true SPI devices as such (which would transfer data in both directions at the same time), they are more like 3 wire serial devices that are compatible with SPI masters.
You can think of SPI as a pair of 8 bit shift registers, one in the master and one in the slave. The last bit output from the master is connected to the first bit input of the slave (labelled Master Out Slave In, or MOSI) and the last bit from the slave output is connected to the first bit input of the master (labelled Master In Slave Out, or MISO). In addition the slave's MISO output buffer is tri-stated when its chip select is negated. In this way when a device is accesssed the CLK signal, which is always driven by the master, clocks data into the slave from the master and out of the slave into the master at the same time. 8 clocks transfers a single byte from the master to the slave and from the slave to the master.
Stupid me. I2C has addresses SPI has chip select. Wikipedia has an article about SPI and shows a daisy chain connection example. Do SPI devices typically support this or is it something that is mentioned in the datasheet if it is supported?
Got it working! I am not that stupid after all ....
But the request for information about SPI and I2C stands.
Best Regards
--
PIC - ARM - DISPLAYS - RELAYS - MODULES - CONVERTERS - I2C - SPI -
KEYPADS - ACCESSORIES
http://www.byvac.com (I am just a satisfied customer)
Multiple SPI devices are supported through the /S signal- chip select. Your CPU will select one line low , for whichever device it wants to talk to, with all other device selects high. Many CPUs support SPI directly, as oppesed to 'bit bang'. Be sure you read the spec on 'max speed' of the SPI peripheral you are using, and make sure you DON't exceed that speed with your CPU. Apart from that, they are simple. Exactly the same as in the old days of Eproms.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.