LH79524/LH79525 User’s Guide
Universal Serial Bus Device
Version 1.0
17-23
17.2.3.4 Control Status Register 1 for IN EP 1, 2, and 3 (INCSR1)
The INCSR1 register maintains the control and status bits for IN endpoints. Software
should only access this register for an IN endpoint after the endpoint has been configured
via INCSR2. The INDEX register must be used to write and read INCSR1.
Table 17-30. INCSR1 Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
CLRT
OG
SENT_STALL
S
E
N
D
_STALL
F
IFO_FLU
S
H
UN
DERRUN
FI
FO
_NE
IN
_PKT_RD
Y
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TYPE
RO
RO
RO
RO
RO
RO
RO
RO
RO
RW
RW
RW
RW
RW
RW
RW
ADDR
0xFF 0x044
(with the INDEX register set to IN endpoint 1, 2, or 3)
Table 17-31. INCSR1 Fields
BITS
NAME
FUNCTION
31:7
///
Reserved
Reading returns 0. Write the reset value.
6
CLRTOG
Clear Data Toggle
The Serial Interface Engine (SIE) toggles the Data
PID sequence identifier for USB transactions with multiple data packets.
In the case of an error condition that requires the USB transaction to be
re-synchronized, this bit must be programmed to 1 by software to reset
the data toggle so that the SIE will transmit a DATA0 packet identifier on
the succeeding transfer. This bit is automatically cleared to 0 when the
USB Device reads it.
1 = Data Toggle bit cleared
0 = No effect on Data Toggle
5
SENT_STALL
STALL Send Acknowledge
The USB block programs this bit to 1 when
a STALL handshake is issued to an IN token by the USB Host, in re-
sponse to software programming the SEND_STALL bit to 1. When the
USB issues a STALL handshake, IN_PKT_RDY is cleared to 0. Clear this
bit by writing a 0 to it.
1 = STALL handshake issued by USB to an in IN token in response to
software setting the SEND_STALL bit
0 = Normal operation
4
SEND_STALL
Send STALL Handshake to USB
Software must program this bit to 1
to issue a STALL handshake to the next IN token. The USB reads the bit
and issues a STALL handshake. Software must program the bit to 0 to
end the STALL condition.
1 = Issue a STALL handshake to the USB Host
0 = End the STALL condition