Hi There,
Currently i am developing a usb to parallel interfacing devece using Cypress EZ-USB FX2LP(CY7C68013a) controller.
this controller having a 8051 mcu in its core.

This controller is having 8052 standard interrupts as well as usb specific additional interrupts.
I am able to use usb specific interrupts and 8052 standard interrupts individually.
But while i use both type of interrupts(timer 0 and USBINT) together, both of them are not working.

Detail explanation with code given below.

i have written a timer-0 ISR as follows.
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void isr_timer(void) interrupt 1 using 1{
BYTE i;
TR0 = 0;

// printf("i");
sendtoPC("Interrupted");
TF0=1;
TR0 = 0;
}
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and timer initialization function as follows
--------------------------------------------------------------------------------------------
void init_timer0(){
TMOD = TMOD | 0x01;
TH0 = 0xff;
TL0 = 0xf0; // starts Timer 0
PT0 = 0;
ET0 = 1;
EA = 1;
TR0 = 1;
}

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The printf() and sendtoPC() function is used to print a string in hyper terminal.
On executing Independently this two functions are working fine.
But when i am inserting it in bulkloop code(cypress sample code uses USBINT interrupts) it is failing to enumerate and the message from ISR is not printing in hyper terminal.
I have modified the bulkloop code as follows..
-----------------------------------------------------------------------------------------------------------------
void main(void)
{
DWORD i;
WORD offset;
DWORD DevDescrLen;
DWORD j=0;
WORD IntDescrAddr;
WORD ExtDescrAddr;
// BYTE loc;
// BYTE k;
// Initialize Global States
Sleep = FALSE; // Disable sleep mode
Rwuen = FALSE; // Disable remote wakeup
Selfpwr = FALSE; // Disable self powered
GotSUD = FALSE; // Clear "Got setup data" flag

setup_uart(); //setup the serial communication with PC.
sendtoPC("Hello"); //test message
TD_Init();
init_timer0(); //initialize timer

_ _ _ _ _ _ _ _
-------------------------------------------------------------------------------------------
without calling the init_timer0() function it is enumerating finely but after calling init_timer0() is detecting as unknown device, after debugging i came to know that SetupCommand(); function is not calling i.e. ISR_Sudav interrupt is not occurring .


So please explain me why this timer interrupt is affecting USB interrupts (Sudav, sutok..etc).
How to use a timer interrupt with bulkloop code.

Thanks in advance.

Warm Regards
rishi