26 USB
S1C38000 TECHNICAL MANUAL
EPSON
247
bits 7–0
Endpoint 3 Max Packet Size Bits [7:0]
This register specifies the maximum packet size for endpoint 3 in units of 8 bytes
(default = 64 bytes). It can be read by the host through the endpoint 3 descriptor.
bits 7–0
Transmit FIFO Data Bits [7:0]
This register is used by the S1C38000 to write data to the transmit FIFO. The FIFO is
read by the USB host using bulk or isochronous transfers from endpoint 4.
bits 7–0
Transmit FIFO Count Bits [7:0]
This register returns the number of transmit FIFO entries containing valid entries.
Values range from 0 (empty) to 64 (full).
bit 5
Transmit FIFO Valid
If set, this bit allows the data in the Transmit FIFO to be read by the next read from the
USB host. This bit is automatically cleared by a USB host read. This bit is only used if
bit 0 in USB[74h] Index [0Ch] is set.
bit 4
Transmit FIFO Flush
Writing to this bit causes the transmit FIFO to be flushed. Reading this bit always
returns a 0.
bit 3
Transmit FIFO Overflow
If set, this bit indicates that an attempt was made by the S1C38000 to write to the
transmit FIFO when the transmit FIFO was full. Writing a 1 clears this bit.
bit 2
reserved
This bit must be set to 0.
bit 1
Transmit FIFO Full (Read Only)
If set, this bit indicates that the transmit FIFO is full.
bit 0
Transmit FIFO Empty (Read Only)
If set, this bit indicates that the transmit FIFO is empty.
Endpoint 3 Maximum Packet Size Register
USB[4Ch]
Default = 0000 0008h
Read/Write
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Endpoint 3 Max Packet Size
15
14
13
12
11
10
98
76543210
Endpoint 4 Transmit FIFO Data Register
USB[50h]
Write Only
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Transmit FIFO Data
15
14
13
12
11
10
98
76543210
Endpoint 4 Transmit FIFO Count Register
USB[54h]
Default = 0000 0000h
Read Only
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Transmit FIFO Count
15
14
13
12
11
10
98
76543210
Endpoint 4 Transmit FIFO Status Register
USB[58h]
Default = 0000 0001h
Read/Write
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Transmit
FIFO
Valid
Transmit
FIFO
Flush
Transmit
FIFO
Overflow
reserved
Transmit
FIFO Full
(RO)
Transmit
FIFO
Empty
(RO)
15
14
13
12
11
10
98
76543210