USB97C100 Standard Microsystems Corporation, USB97C100 Datasheet - Page 30

• Manufacturer Part Number: USB97C100
• Description: USB97C100 Multi-endpoint Usb Peripheral Controller(not Recommended For Designs)
• Manufacturer: Standard Microsystems Corporation

8237 (ISADMA) REGISTER DESCRIPTION
Memory Map
The actual packet may be composed of up to 10 different 128 byte non-contiguous packets, but the MMU re-maps
the internal addresses automatically such that the 8237 and 8051 only need to reference the packet number and
offset within the packet. For example, suppose a 312 (0x138) byte packet is received by the SIEDMA from the host.
The patented MMU allocates 384 bytes for the packet (including an 8 byte status header) and returns a PNR tag of
0x0A. The SIEDMA engine will place 0x0A in the receive packet queue and notify the 8051. The 8051 will take that
PNR, examine the packet through its own PNR/Pointer registers, and determine the offset for the payload data it
wants to transfer from the packet, say 0x027. The address it must calculate for the 8237 base address register would
therefore be 0xA827 (0xA800+0x027). Each channel can be programmed with a different (or same) Packet Number
and offset and the data will appear to it as ordinary contiguous RAM (see table 32 for more information).
Software written to this model will work for virtually any Endpoint number and Buffer size combination.
SMSC DS – USB97C100
8237 MEMORY ADDRESS
0xDC00-0xDFFF
0xCC00-0xCFFF
0xEC00-0xEFFF
0xD800-0xDBFF
0xC800-0xCBFF
0xBC00-0xBFFF
0xAC00-0xAFFF
0xFC00-0xFFFF
0xE800-0xEBFF
0xD400-0xD7FF
0xD000-0xD3FF
0xC400-0xC7FF
0xC000-0xC3FF
0xB800-0xBBFF
0xA800-0xABFF
0xF800-0xFBFF
0xF400-0xF7FF
0xF000-0xF3FF
0xE400-0xE7FF
0xE000-0xE3FF
0xB400-0xB7FF
0xB000-0xB3FF
0xA400-0xA7FF
0xA000-0xA3FF
0x9C00-0x9FFF
0x9800-0x9BFF
0x8C00-0x8FFF
0x8800-0x8BFF
0x9400-0x97FF
0x9000-0x93FF
0x8400-0x87FF
0x8000-0x83FF
0x0000-0x7FFF
Table 38 - ISADMA Memory Map
1k Window to Packet with PNR=0x1F
1k Window to Packet with PNR=0x1E
1k Window to Packet with PNR=0x1D
1k Window to Packet with PNR=0x1C
1k Window to Packet with PNR=0x1B
1k Window to Packet with PNR=0x1A
1k Window to Packet with PNR=0x19
1k Window to Packet with PNR=0x18
1k Window to Packet with PNR=0x17
1k Window to Packet with PNR=0x16
1k Window to Packet with PNR=0x15
1k Window to Packet with PNR=0x14
1k Window to Packet with PNR=0x13
1k Window to Packet with PNR=0x12
1k Window to Packet with PNR=0x11
1k Window to Packet with PNR=0x10
1k Window to Packet with PNR=0x0F
1k Window to Packet with PNR=0x0E
1k Window to Packet with PNR=0x0D
1k Window to Packet with PNR=0x0C
1k Window to Packet with PNR=0x0B
1k Window to Packet with PNR=0x0A
1k Window to Packet with PNR=0x09
1k Window to Packet with PNR=0x08
1k Window to Packet with PNR=0x07
1k Window to Packet with PNR=0x06
1k Window to Packet with PNR=0x05
1k Window to Packet with PNR=0x04
1k Window to Packet with PNR=0x03
1k Window to Packet with PNR=0x02
1k Window to Packet with PNR=0x01
1k Window to Packet with PNR=0x00
32K Window to External ISA RAM
Page 30
DESCRIPTION
Rev. 01/03/2001