mcs7860 MosChip, mcs7860 Datasheet - Page 10

• Manufacturer Part Number: mcs7860
• Description: Usb 2.0 Link Controller With Phy
• Manufacturer: MosChip

MCS7860
USB 2.0 Link Controller with PHY
Configuration Function
RDSM
It interfaces USB device controller’s bulk_in endpoint
to the bridge. It reads from SRAM and sends data to
USB with a maximum packet size of 512 bytes in High
speed (64 bytes in Full speed), per transaction. It works
under the control of bulk_in_endpoint of the
usb_device_controller. RDSM keeps track of the read
pointer, generates read addresses and other signals for
read operation to the memory. At the end of read, it
asserts set_ready for write 0.
Before start of any transfer, the RDSM reads control
information from the last location(Location 257) of the
FIFO. It gets the information about packet length and
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HS on both Ends
FS on both ends
HS write and FS read
FS write and HS read
RequestType
0100_0000
0000_1101
Request
Reads packets from the banks considering the max_packet_size to be 512
bytes.
Reads packets from the banks considering max_packet_size to be 64 bytes.
Full Speed end reads packets considering max_packet_size to be 64 bytes.
The conditions than need to be considered are as follows.
read in chunks of 64 bytes (max) until it encounters a partial packet or zero
lenght packet.
FS device writes 8 packets of 64 bytes length. Switches for every 8 packets.
Stops after writing the zero length packet.
HS read- controller reads 1 packet of 512 bytes (<512 bytes) length.
Stops after reading the zero length packet.
High speed device considers 512 as the max packet size.
The WRSM writes max 512 bytes (or <512) and the FS read controller
Feature Selector
Value
packet type from this read.
It generates the data_ready signal to the bulk_in end-
point so as to enable the usb_device_controller to gen-
erate appropriate handshake to the host.
If the bulk_in_endpoint reports packet error, the RDSM
moves the read_pointers back to their initial value (ini-
tial value of the read_pointer is the value in this register
before the start of this transfer). This enables retry of
packet-reads.
Index
0000
Length
0000
Rev. 1.2