Hi,
I am trying to use this 68HC12 microcontroller in slave mode for I2C
Communication. Is there any sample code which puts the controller in slave
mode and used to communicate with another master? Please help me since i am
working on this for a long time and i could not figure what is wrong. Is it
software code or hardware setup?? Please help me with the sample code.
Thanks,
Dhinesh.
68HC12 Microcontroller as slave
Started by ●July 28, 2015
Reply by ●July 28, 20152015-07-28
This ISR
(and initialization code) for the 68HCS12 and GCC C compiler receives data and
displays by writing to PORTB and sends data from PTIH. This matches switches and
LEDs on a Dragon-12 board.
IBFD = 0x23; // 100KHz operation
// IBFD =
0x35; // 20KHz operation
IBAD =
0x20 << 1; // Slave address is
0x20
IBCR |= 0xC0; // Set IBEN and IBIE
UserIIC = (unsigned int) &iicisr;
iicState = IIC_IDLE;
...
enum
{IIC_IDLE, IIC_TRANSMITTING, IIC_RECEIVING} iicState;
void
INTERRUPT iicisr(void) {
IBSR &= 0x02; // Reset flag
switch (iicState) {
case
IIC_IDLE:
if ((IBSR&0x40)!=0) { // IAAS set -- we are addressed
if ((IBSR&0x04) != 0) { // Slave transmit
IBCR |= 0x10; // set TX
bit
putChar('T');
IBDR = PTIH; // Send switches
iicState = IIC_TRANSMITTING;
} else { // Slave receive
IBDR; // fake read to start receive
iicState = IIC_RECEIVING;
}
}
else { // Toss out anything
here
putChar('I');
IBDR;
}
break;
case
IIC_TRANSMITTING:
if
((IBSR&1) == 0) { // we were ACKed so continue
putChar('T');
IBDR =
PTIH; // Send switches AGAIN!
} else { // We were NAKed
IBCR
&= ~0x10; // Clear TX
bit
IBDR; // Dummy read to finish
iicState =
IIC_IDLE;
}
break;
case
IIC_RECEIVING:
putChar('R');
PORTB =
IBDR; // We will receive one -- additional bytes ignored (Idle state toss
code
IBCR |=
0x80; // Fake write of IBCR
to clear IAAS bit
iicState =
IIC_IDLE;
}
}
-------- Original Message --------
Subject: [68HC12] 68HC12 Microcontroller as slave
From: "Dhinesh Raja Kannan d...@buffalo.edu [68HC12]"
<6...>
Date: Tue, July 28, 2015 10:35 am
To: 6...
Hi,I am trying to use this 68HC12 microcontroller in slave mode for I2C Communication. Is there any sample code which puts the controller in slave mode and used to communicate with another master? Please help me since i am working on this for a long time and i could not figure what is wrong. Is it software code or hardware setup?? Please help me with the sample code.Thanks,Dhinesh.
__._,_.___
Posted by: <t...@almy.us>
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