PXD20RM Datasheet, PDF (607/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

2 _{Look-up table input is running average of the number of ACKs for the self channel counted over the grant total of the last N}
ACKs. ack_count[2:0] controls the parameter N.
14.4.2.2 HPCFG
Offset: 0x88
0
1
2
3
4
5
6
7
8
9
10
11
12
13
R
SETCGLVL
W
CLRCGLVL
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
R
FLTRBAND
W
AVGHIPR
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 14-5. HPCFG register
read/write
14
15
0
0
30
31
0
0
This register controls the hiprio detection logic. The hiprio detection logic detect what percentage of the
requests ACKed by the DRAMC are ACK-ed with a priority larger than 8.
Field
AVGHIPR
FLTRBAND
SETCGLVL
CLRCGLVL
Table 14-4. HPCFG field descriptions
Description
Average number of hi priority requests to DRAM, coded between values 0x1000 and 0x0000
0x1000: 100% high-priority requests
0x0000: 0% high-priority requests
This setting controls the averaging time of the filter used for average_hipriority[12:0]
0: time constant W0 = 8 ACKs, K = 0.125
1: time constant W0 = 16 ACKs, K = 0.0625
2: time constant W0 = 32 ACKs, K = 0.0312
3: time constant W0 = 64 ACKs, K = 0.0156
4: time constant W0 = 128 ACKs, K = 0.0078
5: time constant W0 = 256 ACKs, K = 0.0039
6: time constant W0 = 512 ACKs, K = 0.0020
7: time constant W0 = 1024 ACKs, K = 0.0010
if(average_hipriority[4:12] > SETCGLVL) -> set the congested flag
if(average_hipriority[4:12] < CLRCGLVL) -> clear the congested flag
Freescale Semiconductor
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
14-7