Samsung S3C2440A - Manual (Page 335)

S3C2440A RISC MICROPROCESSOR USB DEVICE
13-7
INTERRUPT REGISTER (EP_INT_REG/USB_INT_REG)
The USB core has two interrupt registers. These registers act as status registers for the MCU when it is
interrupted. The bits are cleared by writing a ‘1’ (not ‘0’) to each bit that was set.
Once the MCU is interrupted, MCU should read the contents of interrupt-related registers and write back to clear
the contents if it is necessary.
Register Address R/W Description Reset Value
EP_INT_REG 0x52000148(L)
0x5200014B(B)
R/W
(byte)
EP interrupt pending/clear register 0x00
EP_INT_REG Bit MCU USB Description Initial
State
EP1~EP4
Interrupt [4:1] R
/CLEAR
SET
For BULK/INTERRUPT IN endpoints:
Set by the USB under the following conditions:
1. IN_PKT_RDY bit is cleared.
2. FIFO is flushed
3. SENT_STALL set.
For BULK/INTERRUPT OUT endpoints:
Set by the USB under the following conditions:
1. Sets OUT_PKT_RDY bit
2. Sets SENT_STALL bit
0
EP0 Interrupt [0] R
/CLEAR
SET Correspond to endpoint 0 interrupt.
Set by the USB under the following conditions:
1. OUT_PKT_RDY bit is set.
2. IN_PKT_RDY bit is cleared.
3. SENT_STALL bit is set
4. SETUP_END bit is set
5. DATA_END bit is cleared (it indicates the end of control
transfer). 0