X25640_8Kb_Serial_EE.. - ISL

Using the Xicor X25640 8kB EEPROMBASIC Stamp I and Ver. D Program Listing (cont.)' ==================================================================' The subroutines for reading and writing the EEPROM.' ==================================================================' Shift data into Shreg.Shin:input DATA_Nlet Shreg=0for i = 1 to 8low CLKlet Shreg=Shreg*2let bit8=DATAhigh CLKnext ioutput DATA_Nreturn' Shift data out of Shreg.Shout:for i = 1 to 8low CLKlet DATA=bit15let Shreg=Shreg*2high CLKnext ireturn' Write EEdata to EEaddr.EEwrite:let Shreg = WriteEEgosub Send_addrlet Shreg = EEdatagosub Shouthigh CSreturn' Change the data line to input.' Clear data byte.' Prepare to get 8 bits.' Data valid on falling edge.' Shift Shreg to the left.' Move data to lsb of variable.' End of clock pulse.' Get another bit.' Restore data line to output.' Shift out 8 bits.' Clear clock bit.' Get bit 7 of Shreg.' Shift register to the left.' Data valid on rising edge of clock.' Send another bit.' Set up the write opcode.' Send it and the address.' Now send the data.' Deactivate the EEPROM.' Read data at EEaddr and put it into EEdata.EEread:let Shreg = ReadEE ' Set up the read opcode.gosub Send_addr ' Send it and the address.gosub Shin' Now get the data.let EEdata = Shreg ' Transfer from Shreg to EEdata.high CS' Deactivate the EEPROM.returnsales / technical support (916) 624-8333 • fax (916) 624-8003pictech@parallainc.com • stamptech@parallaxinc.com Page 8