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'----------------------------------------------------------------------------------------------------' '***********************************************************************' '* WINDT SYSTEMS *' '* BYTES TO PCF8574 v1.2 for CCIMainU1.1 with CCISB *' '* H.J. WINDT *' '* 2004 *' '***********************************************************************' '----------------------------------------------------------------------------------------------------' 'This program will demonstrate sending data to a PCF8574 using the I2C protocol.' 'pcf8574_i2c_address must contain the PCF8574 address/ &b0100(A2)(A1)(A0)0.' 'pcf8574_i2c_data must contain the byte to be sent.' 'The C-CONTROL Main Unit V1.1 is the master' 'Port 1 is the SDA line.' 'Port 2 is the SCL line.' 'Feel free to use and share this software!!' '----------------------------------------------------------------------------------------------------' '*************** INS and OUTS ***************' define sda port[1] define scl port[2] '*******************************************' '**************** VARIABLES ****************' define i2c_byte byte[1] define d7 bit[8] define i2c_error bit[192] define i2c_error_count byte[2] define pcf8574_i2c_address byte[3] define pcf8574_i2c_data byte[4] define loop byte[23] '*******************************************' '**************** CONSTANTS ****************' '*******************************************' '****************** SETUP ******************' '*******************************************' '***************** PROGRAM *****************' #start print"Enter PCF8574 address (64/66/68/70/72/74/76/78)" input pcf8574_i2c_address print"Enter byte to be sent (0 to 255)" input pcf8574_i2c_data gosub send_data_via_i2c_to_pcf8574 goto start '*******************************************' '*************** SUBROUTINES ***************' #send_data_via_i2c_to_pcf8574 #start_i2c i2c_error = 0 sda = 0 scl = 0 i2c_byte = pcf8574_i2c_address 'Transmit address (pcf8574_i2c_address) over the I2C bus' for loop = 1 to 8 sda = d7 gosub scl_pulse i2c_byte = i2c_byte shl 1 next gosub get_ack_i2c if i2c_error then goto stop_i2c i2c_byte = pcf8574_i2c_data 'Transmit byte (pcf8574_i2c_data) over the I2C bus' for loop = 1 to 8 sda = d7 gosub scl_pulse i2c_byte = i2c_byte shl 1 next gosub get_ack_i2c #stop_i2c deact scl deact sda if i2c_error_count > 3 then goto no_ack_or_device if i2c_error then goto send_data_via_i2c_to_pcf8574 'If I2C error then try again' i2c_error_count = 0 return #no_ack_or_device print"No ACK from or no PCF8574 device on I2C address ";pcf8574_i2c_address i2c_error_count = 0 return #get_ack_i2c deact sda if sda then i2c_error = 1 if i2c_error then i2c_error_count = i2c_error_count + 1 #scl_pulse deact scl #clock_stretch if scl = 0 then goto clock_stretch deact scl scl = 0 return '*******************************************' '****************** DATA *******************' '*******************************************' |
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