AcroPack Series AP560
CAN Bus Interface Module
- 68 -
Reliability Prediction
MTBF (Mean Time Between Failure):
MTBF in hours using MIL-HDBK-217F,
FN2.
Per MIL-HDBK-217, Ground Benign, Controlled, G
B
G
C
Temperature
MTBF (Hours)
MTBF (Years)
Failure Rate (FIT
1
)
25°C
2,569,129
293.3
389.2
40°C
1,461,758
166.9
684.1
1
FIT is Failures in 10
9
hours.
PCIe Bus Specifications
Compatibility .................................. Conforms to PCI Express Base Specification, Revision 2.1
Line Speed ...................................... Gen 1 (2.5Gbps) Available through system connector
Lane Operation .............................. 1-Lane
2K Memory Space Required .......... One Base Address Register (BAR)
Table 6.6 PCIe Bus Data Rates
PCIe Gen 1 (1 lane)
Giga bit / second
Bytes / second
Signaling Rate
2.5 Gb/s
312 Mbyte/s
Ideal Rate
1
2 Gb/s
250 Mbyte/s
Header Burden plus 4byte
Sample Rate
2
0.332 Gb/s
41.6 Mbyte/s
Actual Measured 4 Byte
Read Rate
3
0.019 Gb/s
2.35 Mbytes/s
Actual Measured DMA 4
Byte Read Rate
4
0.327 Gb/s
40.9 Mbyte/s
Actual Measured 4 Byte
Write Rate
5
0.320 Gb/s
40 Mbyte/s
Note 1:
PCIe x1 Gen 1 = 2.5GT/s (with 10-bit encoding there is a 20% loss in possible
throughput due to encoding) giving 2.0 G bits/sec or 250M Bytes/sec.
Note 2:
A header for address and read/write command is sent with every packet.
This header is 20 Bytes with data payload of 4 Bytes (for a typical AcroPack). For each
4 Byte data sample, 24 Bytes are sent.
250𝑀𝐵𝑦𝑡𝑒/𝑠
24
𝐵𝑦𝑡𝑒𝑠
=
10.4 M samples/sec or 41.6 M Bytes/sec or 0.332 G bit/sec
Note 3:
For a typical AcroPack measured back to back 4 Byte read operations
completing every 1.7usec. A read operation starts with a host read request. The
AcroPack must process the read and fetch the data and then generated the
completion back to the host. The host then sends a message back that says I got it.
This back and forth hand shaking slows down individual reads.
Note 4:
DMA Read of 1024 sample takes 100us. Each sample is 4 Bytes.
100us/1024=0.0977us per sample or 4/0.0977us = 40.94Mbyte/s. DMA is used to
improve data transfer speed on the AP341/2 and AP225/235.
Note 5:
Simple write operations are just as fast as DMA read operations. Write data
is presented to the AcroPack in one transaction. Measured 4-byte back to back write
accesses taking place every 100ns.
Содержание AcroPack AP560
Страница 28: ...AcroPack Series AP560 CAN Bus Interface Module 28 Figure 2 Standard Data Frame...
Страница 30: ...AcroPack Series AP560 CAN Bus Interface Module 30 Figure 3 Extended Data Frame...
Страница 32: ...AcroPack Series AP560 CAN Bus Interface Module 32 Figure 4 Remote Frame...
Страница 34: ...AcroPack Series AP560 CAN Bus Interface Module 34 Figure 5 Error Frame...