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NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 09:03
by HaWe
(because it's more a compiler or syntax problem, I moved this post from the Tetrix hardware thread to the software forum...)
I just tried my first Tetrix Motor Control program, but it doesn't compile!
(Bricxcc 3.3.8.9. built 3.11.2010)
Code: Select all
// #include "nxcio.h"
void TXMotorOn(byte NXTport, byte TXmotor, char percentage)
{
byte devAddr, modeReg, powerReg;
char result;
devAddr = (TXmotor+2)&14;
modeReg = 0x44 + (TXmotor % 2)*3;
powerReg= 0x45 + (TXmotor % 2);
// NXTsensorPort, I2Caddress, 44H byte Motor_mode: 0=power control
result=WriteI2CRegister(NXTport, devAddr, modeReg, 0);
// NXTsensorPort, I2Caddress, 45H s/byte Motor_power: e.g. 50 =50%
result=WriteI2CRegister(NXTport, devAddr, powerReg, percentage);
}
task main(){
TXMotorOn(0, 1, 50);
Wait(2000);
TXMotorOn(0, 1,-50);
Wait(2000);
TXMotorOn(0, 1, 0);
Wait(2000);
while (true);
}
# Error: Invalid constant expression: __TXMotorOn_7qG2_modeReg_7qG2_000
File "c:\Temp\temp.nxc" ; line 15
# set __WDSC_SensorRegister, __TXMotorOn_7qG2_modeReg_7qG2_000
#----------------------------------------------------------
# Error: Invalid constant expression: __TXMotorOn_7qG2_powerReg_7qG2_000
File "c:\Temp\temp.nxc" ; line 17
# set __WDSC_SensorRegister, __TXMotorOn_7qG2_powerReg_7qG2_000
#----------------------------------------------------------
2 errors during compilation
what's wrong???
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 09:29
by mightor
I did some experimentation and it seems that if the register is not known at compile time then it just won't work.
Code: Select all
result=WriteI2CRegister(NXTport, devAddr, powerReg, percentage);
breaks
Code: Select all
result=WriteI2CRegister(NXTport, devAddr, 0x45, percentage);
compiles fine.
So you need to use the standard method of I2C communication, not this short cut.
- Xander
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 09:42
by HaWe
thx for your hint, Xander! I already was almost back to despair.
I will post it to the wishlist, but can you pls tell me how to rebuild the code to the standard method in the meantime?
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:11
by mightor
Try this, it hasn't been tested, of course. I based the code on other stuff I've written before.
Code: Select all
// #include "nxcio.h"
void TXMotorOn(byte NXTport, byte TXmotor, char percentage)
{
const byte retLen = 0;
byte modeMsg[];
byte powerMsg[];
byte devAddr, modeReg, powerReg;
char result;
devAddr = (TXmotor+2)&14;
modeReg = 0x44 + (TXmotor % 2)*3;
powerReg= 0x45 + (TXmotor % 2);
// Create the message arrays
ArrayBuild(modeMsg, devAddr, modeReg);
ArrayBuild(powerMsg, devAddr, powerReg, percentage);
// Send the first message as soon as the bus is ready
while ((I2CCheckStatus(NXTport) == STAT_COMM_PENDING) && (I2CCheckStatus(NXTport) != NO_ERR)) Yield();
if(I2CWrite(NXTport, retLen, modeMsg) != NO_ERR)
return;
// Send the second message when the first one is done
while ((I2CCheckStatus(NXTport) == STAT_COMM_PENDING) && (I2CCheckStatus(NXTport) != NO_ERR)) Yield();
if(I2CWrite(NXTport, retLen, powerMsg) != NO_ERR)
return;
}
task main(){
TXMotorOn(0, 1, 50);
Wait(2000);
TXMotorOn(0, 1,-50);
Wait(2000);
TXMotorOn(0, 1, 0);
Wait(2000);
while (true);
}
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:14
by mightor
The first message needs to built up like this:
Code: Select all
ArrayBuild(modeMsg, devAddr, modeReg, 0);
My bad.
- Xander
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:17
by mightor
This code should do what you need:
Code: Select all
long MyWriteI2CRegister(byte port, byte address, byte register, byte regvalue) {
const byte retLen = 0;
byte msg[];
// Create the message array
ArrayBuild(msg, address, register, regvalue);
// Send the first message as soon as the bus is ready
while ((I2CCheckStatus(port) == STAT_COMM_PENDING) && (I2CCheckStatus(port) != NO_ERR)) Yield();
return I2CWrite(port, retLen, msg);
}
Again, not tested
- Xander
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:27
by HaWe
thx a lot again, Xander.
I tried the new code with the new ArrayBuild,
it compiles without error,
mux power is on,
the NXT screen says "running"
- but nothing happens.
I surely will therefore have to wait for John's Tetrix implementation.
---
acc. to your
Code: Select all
MyWriteI2CRegister(byte port, byte address, byte register, byte regvalue)
will it be possible to pass also a
int or a
long as a regvalue (e.g., for passing encoder values)?
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:32
by mightor
doc-helmut wrote:will it be possible to pass also a int or a long as a regvalue (e.g., for passing encoder values)?
Nope, as long as NXC doesn't support function overloading it can't be done with a single function name.
- Xander
Re: NXC: WriteI2CRegister compile error
Posted: 05 Dec 2010, 10:53
by HaWe
ok, thx, but I must admit: it is even much harder than I thought with the I2C motor program for Tetrix
But that's not a WriteI2CRegister compile issue any longer.
- thread can be closed -
Re: NXC: WriteI2CRegister compile error
Posted: 07 Dec 2010, 16:47
by afanofosc
I am fixing this problem in WriteI2CRegister so that you can pass in a variable or a constant.
John Hansen