pef20320 Infineon Technologies Corporation, pef20320 Datasheet - Page 176

• Manufacturer Part Number: pef20320
• Description: Multichannel Network Interface Controller For Hdlc With 32 Channels
• Manufacturer: Infineon Technologies Corporation

User’s Manual
5.1.2
All of the test loops are closed (activated) and opened (deactivated) by setting/resetting
the appropriate combination of bits in the Action Specification (Table 10). Any unlisted
combination of LOC, LOOP and LOOPI is an invalid operation. Although the data sheet
(Data Sheet 08.93) specifically states that loops must be left (opened) by issuing the
reset pin to ‘1’, there are exceptions to this rule. Generally, the test loops can be opened
by software. There are several cases that must be examined and these will be discussed
in the next section.
When closing (activating) a test loop, the IN, ICO, IM, RES, and IA bits should equal ‘0’
and PCM and MFL should be set to the appropriate values.
Table 10
Test Loop Activation
Test Loop
Internal complete
Internal channelwise
External complete
External channelwise
No loop
The following recommended procedure for activating a test loop assumes that the
MUNICH32 has been fully initialized and the user desires to activate a test loop on
channel x:
• Initialize Rc and Tx channel as appropriate for type of test loop.
• Close (activate) the test loop.
• Perform test functions (transmit/receive data, check for interrupts, errors, etc.)
• Open (deactivate) the test loop.
• Perform Rc and Tx off function.
Note: While the test loop is activated, do not execute the transmit off command. It will
5.1.3
As mentioned previously, a test loop can be opened (deactivated) by software. To
deactivate a test loop a new ASP should be issued with LOC, LOOP, and LOOPI = 0 and
all other bits should be set to the previous values used during activation. Listed below
are the possible test loop operations that can be activated with software and those
requiring a hardware reset. Table 11 is provided as a graphical representation of this
information.
not have the effect of resetting the transmit formatter.
Test Loop Activation
Test Loop Deactivation and Switching
LOC
0
1
0
1
0
176
LOOP
0
0
1
1
0
LOOPI
0
1
1
0
0
ASP
xxxxxx08
xxxxxx28
xxxxxx10
xxxxxx30
xxxxxx00
Application Notes
PEB 20320
H
H
H
H
H
01.2000