#
# (C) 2012 Travis Goodspeed <travis at radiantmachines.com>
#
-# This code is being rewritten and refactored. You've been warned!
+# WORKING COPY
+# Currently being updated by Siege Technology's ENGS89 team
+# Primary contact: Theodore Sumers <ted.sumers at gmail.com>
+# ADDED FUNCTIONALITY:
+# 10.4/41.6/83.3 kHz sniffing
+# setbitrate
+# debugs on TX and RX packet
+# int-based state change reqs for preserving state
#
# The MCP2515 is a CAN Bus to SPI adapter from Microchip Technology,
adapter on the Goodthopter10 hardware."""
MCPMODES=["Normal","Sleep","Loopback","Listen-only","Configuration",
"UNKNOWN","UNKNOWN","PowerUp"];
+
def MCPsetup(self):
"""Sets up the ports."""
self.SPIsetup();
self.MCPreset(); #Reset the chip.
-
# We're going to set some registers, so we must be in config
# mode.
self.MCPreqstatConfiguration();
# If we don't enable promiscous mode, we'll miss a lot of
# packets. It can be manually disabled later.
- self.poke8(0x60,0xFF); #TODO Does this have any unpleasant side effects?
-
- #Set the default rate.
- self.MCPsetrate();
-
+ #self.poke8(0x60,0xFF); #TODO Does this have any unpleasant side effects?
+ self.poke8(0x60,0x66); #Wanted FF, but some bits are reserved.
+
#Array of supported rates.
- MCPrates=[100,125,250,500,1000];
+ MCPrates=[10.4, 41.6, 83.3, 100, 125, 250, 500, 1000];
+
+ def MCPreset(self):
+ """Reset the MCP2515 chip."""
+ self.SPItrans([0xC0]);
+
+
+ ################ SETTING BAUD RATE ################
+
def MCPsetrate(self,rate=125):
"""Sets the data rate in kHz."""
# Now we need to set the timing registers. See chapter 5 of
# the MCP2515 datasheet to get some clue as to how this
- # arithmetic of this works, as my comments here will likely be
- # rambling, incoherent, and unchanged after I get the infernal
- # thing working.
-
- # First, we must chose a Time Quanta (QT) which is used to
- # define the durations of these segments. Section 5.3
- # suggests setting BRP<5:0> to 0x04 to get a TQ=500ns, as a 20
- # MHz crystal gives a clock period of 50ns. This way, for 125
- # kHz communication, the bit time must be 16 TQ.
-
- # A bit consists of four parts:
- # 1: SyncSeg 1 TQ
- # 2: PropSeg 2 TQ
- # 3: PhaseSeg1 (PS1) 7 TQ
- # 4: PhaseSeg2 (PS2) 6 TQ
-
- # CNF1 with a prescaler of 4 and a SJW of 1 TQ. SJW of 4
- # might be more stable.
- #self.poke8(0x2a,0x04);
-
- # CNF2 with a BLTMODE of 1, SAM of 0, PS1 of 7TQ, and PRSEG of 2TQ
- #self.poke8(0x29,
- # 0x80 | # BTLMODE=1
- # (6<<3) | # 6+1=7TQ for PHSEG1
- # (1) # 1+1=2TQ for PRSEG
- # );
-
- #CNF3 with a PS2 length of 6TQ.
- #self.poke8(0x28,
- # 5 #5+1=6TQ
- # );
+ # arithmetic of this works.
+
+ #STORE the prior status
+ oldstatus=self.MCPcanstatint();
+ print "Setting rate of %i kHz." % rate;
+ #print "Current state is %s." % self.MCPcanstatstr();
+ self.MCPreqstatConfiguration();
+ # print "Switched to %s state." % self.MCPcanstatstr();
- #These are the new examples.
- if rate==125:
+ if rate>41 and rate<42:
+ # NOT CHECKED: based on kvaser website.
+ # Sets baud rate for 41.6 kbps
+ CNF1=0x8e;
+ CNF2=0xa3;
+ CNF3=0x05;
+ elif rate>10 and rate<11:
+ # NOT CHECKED: based on kvaser website.
+ # Sets baud rate for 10.4 kbps
+ CNF1=0xbb;
+ CNF2=0xa3;
+ CNF3=0x05;
+ elif rate==125:
#125 kHz, 16 TQ, not quite as worked out above.
CNF1=0x04;
CNF2=0xB8;
CNF1=0x04;
CNF2=0xBA;
CNF3=0x07;
+ elif rate>83 and rate<83.5:
+ #83+1/3 kHz, 8 TQ
+ # 0.04% error from 83.30
+ CNF1=0x0E;
+ CNF2=0x90;
+ CNF3=0x02;
elif rate==250:
#256 kHz, 20 TQ
CNF1=0x01;
self.poke8(0x2a,CNF1);
self.poke8(0x29,CNF2);
self.poke8(0x28,CNF3);
-
- def MCPreset(self):
- """Reset the MCP2515 chip."""
- self.SPItrans([0xC0]);
+
+ # and now return to whatever state we were in before
+ self.MCPreqstat(oldstatus);
+ #print "Reverted to %s." % self.MCPcanstatstr();
+
+
+ ################# STATE MANAGEMENT ##################
+
def MCPcanstat(self):
"""Get the CAN Status."""
return self.peek8(0x0E);
+ def MCPcanstatstr(self):
+ """Read the present status as a string."""
+ opmod=self.MCPcanstatint();
+ return self.MCPMODES[opmod];
+ def MCPcanstatint(self):
+ """Read present status as an int."""
+ return self.MCPcanstat()>>5;
+
+
+ def MCPreqstat(self, state):
+ """Set the CAN state."""
+ if state==0:
+ self.MCPreqstatNormal();
+ elif state==1:
+ self.MCPreqstatSleep();
+ elif state==2:
+ self.MCPreqstatLoopback();
+ elif state==3:
+ self.MCPreqstatListenOnly();
+ elif state==4:
+ self.MCPreqstatConfiguration();
+ else:
+ print "Invalid state entered; defaulting to Listen-Only"
+ self.MCPreqstatListenOnly();
def MCPreqstatNormal(self):
"""Set the CAN state."""
state=0x0;
state=0x4;
self.MCPbitmodify(0x0F,0xE0,(state<<5));
- def MCPcanstatstr(self):
- """Read the present status as a string."""
- status=self.MCPcanstat();
- opmod=(status&0xE0)>>5;
- return self.MCPMODES[opmod];
+ #################### RX MANAGEMENT #####################
+
def MCPrxstatus(self):
"""Reads the RX Status by the SPI verb of the same name."""
data=self.SPItrans([0xB0,0x00]);
def MCPreadstatus(self):
"""Reads the Read Status by the SPI verb of the same name."""
- #See page 67 of the datasheet for the flag names.
+ #See page 69 of the datasheet for the flag names.
data=self.SPItrans([0xA0,0x00]);
return ord(data[1]);
-
- def MCPrts(self,TXB0=False,TXB1=False,TXB2=False):
- """Requests to send one of the transmit buffers."""
- flags=0;
- if TXB0: flags=flags|1;
- if TXB1: flags=flags|2;
- if TXB2: flags=flags|4;
-
- if flags==0:
- print "Warning: Requesting to send no buffer.";
-
- self.SPItrans([0x80|flags]);
+
def readrxbuffer(self,packbuf=0):
"""Reads the RX buffer. Might have old data."""
data=self.SPItrans([0x90|(packbuf<<2),
- 0x00,0x00, #SID
- 0x00,0x00, #EID
- 0x00, #DLC
- 0x00, 0x00, 0x00, 0x00,
- 0x00, 0x00, 0x00, 0x00
- ]);
- return data[1:len(data)];
- def writetxbuffer(self,packet,packbuf=0):
- """Writes the transmit buffer."""
- self.SPItrans([0x40|(packbuf<<1)]+packet);
+ 0x00,0x00, #SID
+ 0x00,0x00, #EID
+ 0x00, #DLC
+ 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00
+ ]);
+ return data[1:len(data)];
+
def rxpacket(self):
"""Reads the next incoming packet from either buffer.
- Returns None immediately if no packet is waiting."""
+ Returns None immediately if no packet is waiting."""
status=self.MCPrxstatus()&0xC0;
if status&0x40:
#Buffer 0 has higher priority.
return self.readrxbuffer(1);
else:
return None;
+
+ ################# TX MANAGEMENT ##################
+
+ def MCPrts(self,TXB0=False,TXB1=False,TXB2=False):
+ """Requests to send one of the transmit buffers."""
+ flags=0;
+ if TXB0: flags=flags|1;
+ if TXB1: flags=flags|2;
+ if TXB2: flags=flags|4;
+
+ if flags==0:
+ print "Warning: Requesting to send no buffer.";
+ if self.MCPcanstat()>>5!=0:
+ print "Warning: currently in %s mode. NOT in normal mode! May not transmit." %self.MCPcanstatstr();
+ self.SPItrans([0x80|flags]);
+
+ def writetxbuffer(self,packet,packbuf=0):
+ """Writes the transmit buffer."""
+
+ self.SPItrans([0x40|(packbuf<<1)]+packet);
+ #READ BACK BUFFER 0 to check what we're about to send out
+ data=self.SPItrans([0x03, 0x31,
+ 0x00,0x00, #SID
+ 0x00,0x00, #EID
+ 0x00, #DLC
+ 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00
+ ]);
+ print "about to transmit:" + self.packet2str(data[2:len(data)]);
+
def txpacket(self,packet):
"""Transmits a packet through one of the outbound buffers.
As usual, the packet should begin with SIDH.
For now, only TXB0 is supported."""
+
self.writetxbuffer(packet,0);
+
+ #self.SPItrans([0x81]);
self.MCPrts(TXB0=True);
+
+
+ ############### UTILITY FUNCTIONS #################
+
def packet2str(self,packet):
"""Converts a packet from the internal format to a string."""
toprint="";
"""Read a byte from the given address. Untested."""
data=self.SPItrans([0x03,adr&0xFF,00]);
return ord(data[2]);
- def MCPbitmodify(self,adr,mask,data):
- """Writes a byte with a mask. Doesn't work for many registers."""
- data=self.SPItrans([0x05,adr&0xFF,mask&0xFF,data&0xFF]);
- return ord(data[2]);
def poke8(self,adr,val):
"""Poke a value into RAM. Untested"""
self.SPItrans([0x02,adr&0xFF,val&0xFF]);
+ newval=self.peek8(adr);
+ if newval!=val:
+ print "Failed to poke %02x to %02x. Got %02x." % (adr,val,newval);
+ print "Are you not in idle mode?";
return val;
+ def MCPbitmodify(self,adr,mask,data):
+ """Writes a byte with a mask. Doesn't work for many registers."""
+ data=self.SPItrans([0x05,adr&0xFF,mask&0xFF,data&0xFF]);
+ return ord(data[2]);
+
+############### DEBUG UTILITIES: STATUS MESSAGES ##############
+
+# def MCPrxstatusmessage(self):
+# """Returns string indicating status of RX buffers"""
+# status = self.MCPrxstatus();
+#
+# if status < 64:
+# print "No RX message";
+# elif status < 128:
+# print "Message in RXB0";
+# elif status < 192:
+# print "Message in RXB1";
+# else:
+# print "Messages in both buffers";
+
+
+
+# TXB0TRL = 0x30
+# RXB0CTRL = 0x60
+# CNF3/2/1 = 0x28, 29, 2a
+# CANINTE = 0x2b
+# CANINTF = 0x2c
+# TXRTSCTRL = x0D
+
+
+
\ No newline at end of file
projects / goodfet / blobdiff