
26 USB
S1C38000 TECHNICAL MANUAL
EPSON
245
bits 7–0
Endpoint 1 Receive Mailbox Data Bits [7:0]
This port is used to read data from one of the receive mailbox registers. Data is returned
from the register selected by the Endpoint 1 Index Register. The eight receive mailbox
registers are written by a USB bulk transfer to endpoint 1, and can be used to pass
messages from the USB host to the local CPU. The format and content of the messages
are user defined. If enabled, USB writes to this register can generate a local interrupt.
bits 2–0
Endpoint 2 Index Register Bits [2:0]
This register determines which Endpoint 2 Transmit Mailbox is accessed when the
Endpoint 2 Transmit Mailbox Data Port is read or written. This register is automatically
incremented after the Endpoint 2 Transmit Mailbox Data port is read or written. This
index register wraps around to zero when it reaches the maximum count.
bits 7–0
Endpoint 2 Transmit Mailbox Data Bits [7:0]
This port is used to read or write one of the transmit mailbox registers. The register
being accessed is selected by the Endpoint 2 Index Register. The eight Transmit
Mailbox Registers are written by the S1C38000 and are read by a USB interrupt transfer
from endpoint 2. The transmit mailboxes can be used to pass messages from the
S1C38000 to the USB host. The format and content of the messages are user defined. If
enabled, USB reads from this register can generate a local interrupt.
bits 7–0
Interrupt Polling Interval Bits [7:0]
This register specifies the Endpoint 2 interrupt polling interval in milliseconds. It can be
read by the host through the endpoint 2 descriptor.
Endpoint 1 Receive Mailbox Data Register
USB[24h]
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
Endpoint 1 Receive Mailbox Data
15
14
13
12
11
10
98
76543210
Endpoint 2 Index Register
USB[30h]
Default = 0000 0000h
Read/Write
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Endpoint 2 Index
15
14
13
12
11
10
98
76543210
Endpoint 2 Transmit Mailbox Data Register
USB[34h]
Default = 0000 0000h
Read/Write
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Endpoint 2 Transmit Mailbox Data
15
14
13
12
11
10
98
76543210
Endpoint 2 Interrupt Polling Interval Register
USB[38h]
Default = 0000 00FFh
Read/Write
n/a
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
n/a
Interrupt Polling Interval
15
14
13
12
11
10
98
76543210