HbStart
Positron16 · Revision 1.1.3.5 · PDF page 155
Syntax
HbStart
Overview
Send a Start condition to the I2C bus using the microcontroller's MSSP1 module.
Notes.
Because of the subtleties involved in interfacing to some I2C devices, the compiler's standard Hbusin and Hbusout commands were found lacking. Therefore, individual pieces of the I2C protocol may be used in association with the new structure of Hbusin, and Hbusout. See relevant sections for more information.
Example
' Interface to a 24LC32 serial EEPROM
Device = 24FJ64GA002 ' Select the device to compile for
Declare Xtal = 16
Declare Hserial_Baud = 9600 ' USART1 Baud rate
Declare Hrsout1_Pin = PORTB.14 ' Select the pin for TX with USART1
Dim bLoop as Byte
Dim Array[10] as Byte
RPOR7 = 3 ' Make PPS Pin RP14 U1TX
'
' Transmit bytes to the I2C bus
'
HbStart ' Send a Start condition
Hbusout %10100000 ' Target an EEPROM, and send a Write command
Hbusout 0 ' Send the HighByte of the address
Hbusout 0 ' Send the LowByte of the address
For bLoop = 48 to 57 ' Create a loop containing ASCII 0 to 9
Hbusout bLoop ' Send the value of bLoop to the EEPROM
Next ' Close the loop
HbStop ' Send a Stop condition
DelayMs 10 ' Wait for the data to be entered into EEPROM matrix
'
' Receive bytes from the I2C bus
'
HbStart ' Send a Start condition
Hbusout %10100000 ' Target an EEPROM, and send a Write command
Hbusout 0 ' Send the HighByte of the address
Hbusout 0 ' Send the LowByte of the address
HbRestart ' Send a Restart condition
Hbusout %10100001 ' Target an EEPROM, and send a Read command
For bLoop = 0 to 9 ' Create a loop
Array[bLoop] = Hbusin ' Load an array with bytes received
If bLoop = 9 Then HbStop : Else : HbusAck ' Ack or Stop ?
Next ' Close the loop
HrsoutLn Str Array ' Display the Array as a StringSee also : HbusAck, HbRestart, HbStop, Hbusin, Hbusout, HbusAck2, HbRestart,2 HbStop2, Hbusin2, Hbusout2.
