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cchappyboy
Joined: 03 Dec 2008
Posts: 45
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| I have a question about can_putd() function in pic18xxx8.c |
 Posted: Thu Apr 23, 2009 3:52 pm |
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The question is when it want to set tx mask it use can_set_id(TXRXBaID, id, ext) but TXRXBaID is 0xF64h that is the register RXB0EIDL according
pic18xxx8.h. why it need to set tx mask? what is the use for? Thanks for anybody's help!!!
| Code: |
int1 can_putd(int32 id, int * data, int len, int priority, int1 ext, int1 rtr) {
int i;
int * txd0;
int port;
txd0=&TXRXBaD0;
// find emtpy transmitter
//map access bank addresses to empty transmitter
if (!TXB0CON.txreq) {
CANCON.win=CAN_WIN_TX0;
port=0;
}
else if (!TXB1CON.txreq) {
CANCON.win=CAN_WIN_TX1;
port=1;
}
else if (!TXB2CON.txreq) {
CANCON.win=CAN_WIN_TX2;
port=2;
}
else {
#if CAN_DO_DEBUG
can_debug("\r\nCAN_PUTD() FAIL: NO OPEN TX BUFFERS\r\n");
#endif
return(0);
}
//set priority.
TXBaCON.txpri=priority;
//set tx mask
can_set_id(TXRXBaID, id, ext);
//set tx data count
TXBaDLC=len;
TXBaDLC.rtr=rtr;
for (i=0; i<len; i++) {
*txd0=*data;
txd0++;
data++;
}
//enable transmission
TXBaCON.txreq=1;
CANCON.win=CAN_WIN_RX0;
#if CAN_DO_DEBUG
can_debug("\r\nCAN_PUTD(): BUFF=%U ID=%LX LEN=%U PRI=%U EXT=%U RTR=%U\r\n", port, id, len, priority, ext, rtr);
if ((len)&&(!rtr)) {
data-=len;
can_debug(" DATA = ");
for (i=0;i<len;i++) {
can_debug("%X ",*data);
data++;
}
can_debug("\r\n");
}
#endif
return(1);
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 24, 2009 5:32 pm |
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It's possibly a bug in the code.
Here is the code from the mcp2510 driver. It loads the extended ID
into the Transmit Buffer 'n' Extended ID register (lsb byte). Note how
when it sets the tx mask, it's writing to the TXB0EIDL register. This
is the transmitter routine, can_putc(), and it writes the mask to the
transmit mask register.
can-mcp2510.c
| Quote: | if (!b_TXB0CTRL.txreq) {
TXRXBaD0=TXB0D0;
TXBaCTRL=TXB0CTRL;
TXRXBaEIDL=TXB0EIDL;
TXBaDLC=TXB0DLC;
port=0;
//set tx mask
can_set_id(TXRXBaEIDL, id, ext); |
can-mcp2510.h
| Quote: | //transmit buffer n extended identifier
#define TXB0EIDH 0x33
#define TXB0EIDL 0x34
#define TXB1EIDH 0x43
#define TXB1EIDL 0x44
#define TXB2EIDH 0x53
#define TXB2EIDL 0x54
|
But in the can-18xxx8.c driver, CCS is using 0xF64 as the address for the
TXB0EIDL register in the can_putd() function. But 0xF64 is a "Rx" ID
register. The correct address for the "Tx" ID register is 0xF44.
So it looks like a bug in the code. |
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cchappyboy
Joined: 03 Dec 2008
Posts: 45
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| Posted: Thu Apr 30, 2009 10:39 am |
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| Thanks you so much. |
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