AN169

Rev. 2.3

21

4.5. Get_Interrupt_Source

Description:

Returns an 8-bit value indicating the reason(s) for the API interrupt, and clears the USB API

interrupt pending flag(s). This function should be called at the beginning of the user's interrupt

service routine to determine which event(s) has/have occurred.

Supported Devices:

C8051F320/1/6/7, C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D,

C8051F380/1/2/3/4/5/6/7, C8051T320/1/2/3/6/7, C8051T620/1/2/3

Prototype:

BYTE Get_Interrupt_Source (void)

Parameters:

None

Return Value:

Returns an unsigned 8-bit code indicating the reason(s) for the API interrupt. The code can indi-

cate more than one type of interrupt at the same time. The return values are coded as follows:

0x00

No USB API Interrupts have occurred

0x01

USB_RESET

USB Reset Interrupt has occurred

0x02

TX_COMPLETE

Transmit Complete Interrupt has occurred

0x04

RX_COMPLETE

Receive Complete Interrupt has occurred

0x08

FIFO_PURGE

Command received (and serviced) from the host to purge

the USB buffers

0x10

DEVICE_OPEN

Device Instance Opened on host side

0x20

DEVICE_CLOSE

Device Instance Closed on host side

0x40

DEV_CONFIGURED

Device has entered configured state

0x80

DEV_SUSPEND

USB suspend signaling present on bus

4.6.

USB_Int_Enable

Description:

A call to this function enables the USB API to generate interrupts. If enabled, a USB API interrupt

is generated on the following API events:

1. A USB Reset has occurred.

2. A transmit scheduled by a call to Block_Write has completed.

3. The RX buffer is ready to be serviced by a call to Block_Read.

4. A command from the host has caused the USB buffers to be flushed.

5. A Device Instance has been opened or closed by the host.

The cause of the interrupt can be determined by a call to Get_Interrupt_Source. If USB API inter-

rupts are enabled, the user must provide an interrupt service routine with the entry point located

at the interrupt 16 vector (Address = 0x0083). When this function is called, control will transfer to

the interrupt 16 handler within one ms, if any interrupts are currently pending.

Supported Devices:

C8051F320/1/6/7, C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D,

C8051F380/1/2/3/4/5/6/7, C8051T320/1/2/3/6/7, C8051T620/1/2/3

Prototype:

void USB_Int_Enable (void)

Parameters:

None

Return Value:

None