added Makefile switches to change F_CPU

firmware/Makefile

@@ -11,14 +11,17 @@ TARGET=atmega8
 HFUSE=0xc9
 LFUSE=0xef
 
+# crystal frequency
+#F_CPU=12000000
+F_CPU=16000000
 
 # ISP=bsd      PORT=/dev/parport0
 # ISP=ponyser  PORT=/dev/ttyS1
 # ISP=stk500   PORT=/dev/ttyS1
 # ISP=usbasp   PORT=/dev/usb/ttyUSB0
 # ISP=stk500v2 PORT=/dev/ttyUSB0
-ISP=usbasp
-PORT=/dev/usb/ttyUSB0
+ISP=avrisp2
+PORT=usb
 
 help:
 	@echo "Usage: make                same as make help"
@@ -33,11 +36,11 @@ help:
 	@echo "       TARGET=${TARGET}"
 	@echo "       LFUSE=${LFUSE}"
 	@echo "       HFUSE=${HFUSE}"
-	@echo "       CLOCK=12000000"
+	@echo "       CLOCK=${F_CPU}"
 	@echo "       ISP=${ISP}"
 	@echo "       PORT=${PORT}"
 
-COMPILE = avr-gcc -Wall -O2 -Iusbdrv -I. -mmcu=$(TARGET) # -DDEBUG_LEVEL=2
+COMPILE = avr-gcc -Wall -O2 -Iusbdrv -I. -mmcu=$(TARGET) -DF_CPU=${F_CPU} # -DDEBUG_LEVEL=2
 
 OBJECTS = usbdrv/usbdrv.o usbdrv/usbdrvasm.o usbdrv/oddebug.o isp.o clock.o tpi.o main.o
 

firmware/clock.h

@@ -11,9 +11,13 @@
 #ifndef __clock_h_included__
 #define	__clock_h_included__
 
-#define F_CPU           12000000L   /* 12MHz */
+#ifndef F_CPU /* should be defined in Makefile */
+#define F_CPU           16000000L   /* 16MHz */
+#endif
+
 #define TIMERVALUE      TCNT0
-#define CLOCK_T_320us	60
+#define CLOCK_T_320us	(320e-6*F_CPU/64) /* prescaler is 64 as defined below */
+
 
 #ifdef __AVR_ATmega8__
 #define TCCR0B  TCCR0

firmware/usbconfig.h

@@ -35,7 +35,7 @@ the newest features and options.
  * This may be any bit in the port. Please note that D+ must also be connected
  * to interrupt pin INT0!
  */
-#define USB_CFG_CLOCK_KHZ 12000
+#define USB_CFG_CLOCK_KHZ (F_CPU/1000)
 /* Clock rate of the AVR in MHz. Legal values are 12000, 16000 or 16500.
  * The 16.5 MHz version of the code requires no crystal, it tolerates +/- 1%
  * deviation from the nominal frequency. All other rates require a precision