diff --git a/f.sh b/f.sh
new file mode 100644
index 0000000..c579356
--- /dev/null
+++ b/f.sh
@@ -0,0 +1,5 @@
+SYSCLK=36000
+
+sdcc -mmcs51 -DSYSCLK=${SYSCLK} flash.c
+stcgal -t ${SYSCLK} flash.ihx
+
diff --git a/flash.c b/flash.c
new file mode 100644
index 0000000..493b039
--- /dev/null
+++ b/flash.c
@@ -0,0 +1,67 @@
+
+#include <8052.h>
+
+#ifndef FLASH_PIN 
+#define FLASH_PIN P2_0
+#endif
+
+#ifndef IRQFREQ
+#define IRQFREQ 1000L
+#endif
+
+#define FOSC (SYSCLK*1000L)
+
+#define T0_1MS	(65536L-FOSC/12L/IRQFREQ)
+
+#define TCT IRQFREQ/2-1
+
+unsigned char ctr_l =  TCT&0xFF;
+unsigned char ctr_h = (TCT>>8)&0xff;
+unsigned char ctr_w = (TCT>>16)&0xff;
+
+void handler() __interrupt 1 
+{
+	EA=0;
+	__asm
+	mov a, #0xff
+	dec _ctr_l
+	cjne a,_ctr_l, 00001$
+	dec _ctr_h
+	cjne a,_ctr_h, 00001$
+	dec _ctr_w
+	cjne a,_ctr_w, 00001$
+
+	cpl  _P2_0
+	__endasm;
+	
+	ctr_l =  TCT&0xFF;
+	ctr_h = (TCT>>8)&0xff;
+	ctr_w = (TCT>>16)&0xff;
+
+	__asm
+	00001$:
+	__endasm;
+	EA=1;
+}
+
+
+void main()
+{
+	
+	P1=TMOD;
+
+	EA=0;
+
+	TMOD =0; 
+	P1=TMOD;
+
+	TL0 = (T0_1MS) & 0xFF; 	// Initial timer value
+    	TH0 = T0_1MS>>8;	// Initial timer value
+
+
+	TR0 = 1;		// Timer0 start run
+	ET0 = 1;		// Enable timer0 interrupt
+	EA=1;
+
+	while(1);
+}