Hitachi H8S/2215 Series Hardware Manual page 525

Bit Bit Name Initial Value R/W
1 EP4iTR 0
0 EP4iEMPTY 1
Note: * The write value should always be 0 to clear this flag.
Description
R/(W)* EP4i Transfer Request
Set to 1 if the EP4i FIFO is empty when an IN token is
sent form the host to EPi4. The corresponding
interrupt output is EXIRQ0 or EXIRQ1.
R EP4i FIFO Empty
EP4i FIFO has a dual-FIFO configuration. This flag is
set if at least one EP4i FIFO is empty. This flag is
cleared to 0 if EP4i FIFO is full. This flag is a status
flag and cannot be cleared. The corresponding
interrupt output is EXIRQ0 or EXIRQ1.
Rev. 3.0, 10/02, page 467 of 686