Samsung S3C2440A - Manual (Page 342)

USB DEVICE S3C2440A RISC MICROPROCESSOR
13-14
END POINT IN CONTROL STATUS REGISTER (IN_CSR1_REG/IN_CSR2_REG)
Register Address R/W Description Reset Value
IN_CSR1_REG 0x52000184(L)
0x52000187(B)
R/W
(byte)
IN END POINT control status register1 0x00
IN_CSR1_REG Bit MCU USB Description Initial
State
Reserved [7] - - - -
CLR_DATA_
TOGGLE [6] R/W R/
CLEAR
Used in Set-up procedure.
0: There are alternation of DATA0 and DATA1
1: The data toggle bit is cleared and PID in packet will
maintain DATA0 0
SENT_STALL [5] R/
CLEAR
SET Set by the USB when an IN token issues a STALL
handshake, after the MCU sets SEND_STALL bit to
start STALL handshaking. When the USB issues a
STALL handshake, IN_PKT_RDY is cleared 0
SEND_STALL [4] W/R R 0: The MCU clears this bit to finish the STALL
condition.
1: The MCU issues a STALL handshake to the USB. 0
FIFO_FLUSH [3] R/W CLEAR Set by the MCU if it intends to flush the packet in
Input-related FIFO. This bit is cleared by the USB
when the FIFO is flushed. The MCU is interrupted
when this happens. If a token is in process, the USB
waits until the transmission is complete before FIFO
flushing. If two packets are loaded into the FIFO, only
first packet (The packet is intended to be sent to the
host) is flushed, and the corresponding IN_PKT_RDY
bit is cleared 0
Reserved [2:1] - - - -
IN_PKT_RDY [0 R/SET CLEAR
Set by the MCU after writing a packet of data into the
FIFO.
The USB clears this bit once the packet has been
successfully sent to the host.
An interrupt is generated when the USB clears this
bit, so the MCU can load the next packet. While this
bit is set, the MCU will not be able to write to the
FIFO.
If the MCU sets SEND STALL bit, this bit cannot be
set.
0