Information

Universal Serial Bus Interface
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
13-40 Freescale Semiconductor
as shown below. This provides a snooping region of 4 Kbytes to 2 Gbytes within each starting base address
that is programmed by the core. The SNOOPn[20–26] are not used.
Table 13-33 describes the SNOOPn register fields.
13.3.2.25 Age Count Threshold Register (AGE_CNT_THRESH)—Non-EHCI
Note that this register uses big-endian byte ordering and is not defined in the EHCI specification. The age
count threshold (AGE_CNT_THRESH) register provides the aging counter threshold value used to
determine the priority state of the USB DR controller’s internal system interface. This is used to increase
the priority state of the module’s system interface from zero to one. The actual priority level on the system
bus for each state is defined by the PRI_CTRL register. See Section 6.3.1.1, “Address Bus Arbitration with
PRIORITY[0:1],” for more details on bus priority. The threshold value is in units of csb_clk cycles. This
register should be written during system initialization or during normal system operation when the system
bus interface is idle. It can be read at any time.
Offset 0x400 (SNOOP1), 0x404 (SNOOP2) Access: Read/Write
0 19 20 26 27 31
R
Snoop Address — Snoop Enables
W
Reset All zeros
Figure 13-30. Snoop 1 and Snoop 2 (SNOOPn)
Table 13-33. SNOOPn Register Field Descriptions
Bits Name Description
0–19 Snoop address The starting base address for which transactions are snooped.
20–26 — Reserved, should be cleared
27–31 Snoop Enables 0x00 Snooping disabled
0x0B 4-Kbyte snoop range starting at the value defined by SNOOPn[0–19]
0x0C 8-Kbyte snoop range starting at the value defined by SNOOPn[0–18]
0x0D 16-Kbyte snoop range starting at the value defined by SNOOPn[0–17]
0x0E 32-Kbyte snoop range starting at the value defined by SNOOPn[0–16]
0x0F 64-Kbyte snoop range starting at the value defined by SNOOPn[0–15]
0x10 128-Kbyte snoop range starting at the value defined by SNOOPn[0–14]
0x11 256-Kbyte snoop range starting at the value defined by SNOOPn[0–13]
0x12 512-Kbyte snoop range starting at the value defined by SNOOPn[0–12]
0x13 1-Mbyte snoop range starting at the value defined by SNOOPn[0–11]
0x14 2-Mbyte snoop range starting at the value defined by SNOOPn[0–10]
0x15 4-Mbyte snoop range starting at the value defined by SNOOPn[0–9]
0x16 8-Mbyte snoop range starting at the value defined by SNOOPn[0–8]
0x17 16-Mbyte snoop range starting at the value defined by SNOOPn[0–7]
0x18 32-Mbyte snoop range starting at the value defined by SNOOPn[0–6]
0x19 64-M byte snoop range starting at the value defined by SNOOPn[0–5]
0x1A 31-Mbyte snoop range starting at the value defined by SNOOPn[0–4]
0x1B 256-Mbyte snoop range starting at the value defined by SNOOPn[0–3]
0x1C 512-Mbyte snoop range starting at the value defined by SNOOPn[0–2]
0x1D 1-Gbyte snoop range starting at the value defined by SNOOPn[0–1]
0x1E 2-Gbyte snoop range starting at the value defined by SNOOPn[0]