Cypress SL811HS - Manual (Page 14)

SL811HS
Document 38-08008 Rev. *D Page 14 of 32
Endpoint Packet Status [Address a = (EP# * 10h)+3, b = (EP# * 10h)+Bh]. The packet status contains information relative to
the packet that is received or transmitted. The register is defined as follows:
Endpoint Transfer Count [Address a = (EP# * 10h)+4, b =
(EP# * 10h)+Ch]. As a peripheral device, the Endpoint
Transfer Count register is only important with OUT tokens
(host sending the slave data). When a host sends the
peripheral data, the Transfer Count register contains the
difference between the Endpoint Base Length and the actual
number of bytes received in the last packet. In other words, if the Endpoint Base Length register was set for 64 (40h) bytes
and an OUT token was sent to the endpoint that only had 16
(10h) bytes, the Endpoint Transfer Count register has a value
of 48 (30h). If more bytes were sent in an OUT token then the
Endpoint Base Length register was programmed for, the
overflow flag is set in the Endpoint Packet Status register and
is considered a serious error.
USB Control Registers
The USB Control registers manage communication and data
flow on the USB. Each USB device is composed of a collection
of independently operating endpoints. Each endpoint has a unique identifier, which is the Endpoint Number. For more
details about USB endpoints, refer to the USB Specification
1.1, Section 5.3.1.
The Control and Status registers are mapped as follows:
Table 25. Endpoint Packet Status Reg [Address EP0a/b:03h/0Bh, EP1a/b:13h/1Bh, EP2a/b:23h/2Bh, EP3a/b:33h/3Bh]
7 6 5 4 3 2 1 0
Reserved Reserved Overflow Setup Sequence Time-out Error ACK
Bit Position Bit Name Function
7 Reserved Not applicable.
6 Reserved Not applicable.
5 Overflow Overflow condition - maximum length exceeded during receives. This is considered a
serious error. The maximum number of bytes that can be received by an endpoint is deter-
mined by the Endpoint Base Length register for each endpoint. The Overflow bit is only
relevant during OUT Tokens from the host.
4 Setup '1' indicates Setup Packet. If this bit is set, the last packet received was a setup packet.
3 Sequence This bit indicates if the last packet was a DATA0 (0) or DATA1 (1).
2 Time-out This bit is not used in slave mode.
1 Error Error detected in transmission, this includes CRC5/16 and PID errors.
0 ACK Transmission Acknowledge.
Table 26. Endpoint Transfer Count Reg [Address EP0a/b:04h/0Ch, EP1a/b:14h/1Ch, EP2a/b:24h/2Ch, EP3a/b:34h/3Ch]
7 6 5 4 3 2 1 0
EPxCNT7 EPxCNT6 EPxCNT5 EPxCNT4 EPxCNT3 EPxCNT2 EPxCNT1 EPxCNT0
Table 27. Control and Status Register Map
Register Name Address (in Hex)
Control Register 1 05h
Interrupt Enable Register 06h
USB Address Register 07h
Interrupt Status Register 0Dh
Current Data Set Register 0Eh
Control Register 2 0Fh
SOF Low Byte Register 15h
SOF High Byte Register 16h
DMA Total Count Low Byte Register 35h
DMA Total Count High Byte Register 36h