my sketch doesn't know how to link .ino with .h and .s file s

hi!
Arduino IDE can link .ino with .h and .s files, but why can't it do that when I want, heh?
OK, let me explain:
I downloaded the following example form somewhere on this forum.
It's name is BasicSerial, and it contains the following 2 files in .....Arduino\libraries\BasicSerial:

BasicSerial.h:

extern "C" {
void TxByte(char);
}

BasicSerial.s:

#include <avr/io.h>
; the defines are not impotant for my question, but let them be there
#define UART_Port (PORTE-0x20)
#define UART_Tx 1
#define bitcnt r18
#define delayArg 19
#define TXDELAY 44

.global TxByte
TxByte:
cli
sbi UART_Port-1, UART_Tx ; set Tx line to output
ldi bitcnt, 10 ; 1 start + 8 bit + 1 stop
com r24 ; invert and set carry
; etc. some more code here, not important for my question
; asm code..asm code...
reti ; return and enable interrupts

And the BasicSerial.ino is:

#include <BasicSerial.h>
#define LEDPIN PINB1

void setup(){
DDRB |= (1<<LEDPIN); // set LED pin to output mode
}

void serOut(const char* str)
{
while (*str) TxByte (*str++);
}

void loop(){
serOut("Turning on LED\n");
PORTB |= (1<<LEDPIN); // turn on LED
delay(500); // 0.5 second delay
PORTB &= ~(1<<LEDPIN); // turn off LED
delay(1000); // 1 second delay
}

Ok, when I compile BasicSerial.ino, all goes well, no error messages.

My "test" program with similar 2 files in .....Arduino\libraries_TC1test
_TC1test.h:

extern "C" {
void CT1PFC();
}

_TC1test.s

#include <avr/io.h>

.global CT1PFC
CT1PFC:
nop
ret

And my _TC1test.ino:


#include <_TC1test.h>

extern void CT1PCF();

void setup(){
CT1PCF();
}

void loop()
{
}


When I compile the sketch, I get: error: undefined reference to `CT1PCF()
No matter what I try, it doesn't work. WHy doesn't it work and why does BasicSerial example work?
thx

Help!

Which version of the ide are you using?
I mean IMHO s files only got supported in 1.5.5.
Best regards
Jantje

Jantje:
Which version of the ide are you using?
I mean IMHO s files only got supported in 1.5.5.
Best regards
Jantje

I am using 1.0.5.
But why does the BasicSerial example work?
I must try the newest version though.
Thanks!