PIC14000-04/JW 查看數據表（PDF） - Microchip Technology

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PIC14000-04/JW

28-Pin Programmable Mixed Signal Controller

Microchip Technology 

PIC14000

FIGURE 7-17: OPERATION OF THE I2C IN IDLE_MODE, RCV_MODE OR XMIT_MODE

IDLE_MODE (7-bit):

if (Addr_match)

{

Set interrupt;

if (R/W = 1) {

Send ACK = 0;

set XMIT_MODE;

}

else if (R/W = 0) set RCV_MODE;

}

RCV_MODE:

if ((I2CBUF=Full) OR (I2COV = 1))

{ Set I2COV;

Do not acknowledge;

}

else

{

transfer I2CSR → I2CBUF;

send ACK = 0;

}

Receive 8-bits in I2CSR;

Set interrupt;

XMIT_MODE:

While ((I2CBUF = Empty) AND (CKP=0)) Hold SCL Low;

Send byte;

Set interrupt;

if (ACK Received = 1)

{

End of transmission;

Go back to IDLE_MODE;

}

else if (ACK Received = 0) Go back to XMIT_MODE;

IDLE_MODE (10-Bit):

If (High_byte_addr_match AND (R/W = 0))

{ PRIOR_ADDR_MATCH = FALSE;

Set interrupt;

if ((I2CBUF = Full) OR ((I2COV = 1))

{

Set I2COV;

Do not acknowledge;

}

else

{

Set UA = 1;

Send ACK = 0;

While (I2CADD not updated) Hold SCL low;

Clear UA = 0;

Receive Low_addr_byte;

Set interrupt;

Set UA = 1;

If (Low_byte_addr_match)

{

PRIOR_ADDR_MATCH = TRUE;

Send ACK = 0;

while (I2CADD not updated) Hold SCL low;

Clear UA = 0;

Set RCV_MODE;

}

}

}

else if (High_byte_addr_match AND (R/W = 1)

{ if (PRIOR_ADDR_MATCH)

{

send ACK = 0;

set XMIT_MODE;

}

else PRIOR_ADDR_MATCH = FALSE;

}

DS40122B-page 54

Preliminary

© 1996 Microchip Technology Inc.

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