핵심 단어: test registers, special function registers, transmit receive, side registers, DS21Q42, DS21Q44, DS2152, DS2154, DS21352, DS21552, DS21354, DS21554
Abstract: Some special functions are not derivable by using the normal transmit and receive side registers. In order to derive those functions, we need to use the test registers of the following devices: DS21Q42, DS21Q44, DS2152, DS2154, DS21352, DS21552, DS21354, and DS21554. This application note describes the details of using these test registers.
Note: For DS21Q42 and DS21Q44 devices, the Line Interface TEST registers are not applicable.
Test Register Settings for the DS21x52 & DS21Q42
TEST1 (address 7D) can be used for error counter functionality.
TEST1.6
Set High to Enable Test1.5 to control sampling of error counters
TEST1.5
Sample error counters. (See figure below)
Point 1: After TEST1.6 is set high, toggling TEST1.5 clears the counter and starts the error counter.
Point 2: The actual count is transparent to the user while TEST1.5 is set high. The user will then see
the accumulated error count from the time of reset to setting TEST1.5 high.
Point 3: When TEST1.5 is cleared, the error count is latched and the count is reset and allowed to begin
counting.
TEST1.3 resets the one second timer.
TEST2 (address 09) can be used to modify the Attenuation Levels of the device
TEST2.7
TEST2.6
TEST2.5
TEST2.4
TEST2.1
Output
0
1
1
0
X
Rcvr additional 6dB attenuation pad
0
1
1
1
0
Rcvr 20dB monitor mode
0
1
1
1
1
Rcvr 12dB monitor mode
1
0
0
0
1
Bypass equalizer
Common Control bits settings (address 0A)
CCR7.2 = 1
Line Interface Synchronization Interface Enable
CCR7.1 = 1
1 Customer will generate a CDI pattern at TTIP & TRING instead of normal data.
CCR7.0 = 1
TTIP & TRING become open drain
Test Register Settings for the DS21x54 & DS21Q44
TEST1 (address 15) can be used for output test mode and error counter functionality.
TEST1.7 and TEST1.6 can be used to force all outputs into a logic 1, logic 0 or 3-state.
TEST1.7
TEST1.6
Output
0
0
NORMAL OPERATION
0
1
3-STATE
1
0
LOGIC '0'
1
1
LOGIC '1'
TEST1.4 and TEST1.3 can be used for error counter functionality.
TEST1.4
Sample error counters. (See figure below)
TEST1.3
Set High to Enable Test1.4 to control sampling of error counters
Point 1: After TEST1.3 is set high, toggling TEST1.4 clears the counter and starts the error counter.
Point 2: The actual count is transparent to the user while TEST1.4 is set high. The user will then see
the accumulated error count from the time of reset to setting TEST1.4 high.
Point 3: When TEST1.4 is cleared, the error count is latched and the count is cleared.
TEST1.2 =1 converts SR2.0 from TSLIP to Loss of Receive Clock (LORC).
TEST1.0 resets the one second timer.
TEST3 (address AC) can be used to modify the Attenuation Levels of the device
TEST3.7
TEST3.6
TEST3.5
TEST3.4
TEST3.1
Output
0
1
1
0
X
Rcvr additional 6dB attenuation pad
0
1
1
1
0
Rcvr 30dB monitor mode
0
1
1
1
1
Rcvr 12dB monitor mode
1
0
0
0
1
Bypass equalizer
Test Register Settings for the DS2152
CCR6 (address 1E) can be used for error counter functionality.
CCR1.6
Reset one second timer
CCR1.5
Testcount. (See figure below)
Point 1: Setting bit 6 high prohibits the 1 second timer from interfering with the error count.
Point 2: While bit 6 is high, asserting bit 5 allows the counter to begin. The counter read is real time.
TEST2 (Address 09) can be used to modify the Attenuation Levels of the device.
TEST2.6
TEST2.1
TEST2.0
Output
1
0
0
Rcvr additional 6dB attenuation pad
0
1
0
Rcvr 6dB monitor mode
0
0
1
Bypass equalizer
Test Register Settings for the DS2154
>
TEST2 (address19)
OUTPUT TEST MODES TEST2.7 and TEST2.6 can be used to force all outputs into a logic 1, logic 0 or 3-state.
TEST2.7
TEST2.6
Output
0
0
NORMAL OPERATION
0
1
3-STATE
1
0
LOGIC '0'
1
1
LOGIC '1'
TEST2.4 and TEST2.3 can be used for error counter functionality.
TEST2.4
Sample error counters. (See figure below)
TEST2.3
Set High to Enable Test1.4 to control sampling of error counters
Point 1: After TEST2.3 is set high, toggling TEST2.4 clears the counter and starts the error counter.
Point 2: The actual count is transparent to the user while TEST2.4 is set high. The user will then see
the accumulated error count from the time of reset to setting TEST2.4 high.
Point 3: When TEST2.4 is cleared, the error count is latched and the count is cleared.
TEST2.2 will change the definition of RIR.7, RIR.6 and SR2.0.
TEST2.2
RIR.7
RIR.6
SR2.0
0
NORMAL (TESF)
NORMAL (TESE)
NORMAL (TSLIP)
1
RL1, RECEIVE LEVEL BIT 1
RL0, RECEIVE LEVEL BIT 0
LORC, LOSS OF RECEIVE CLOCK
RL1
RL2
Typical Level Received
0
0
+2dB to -7.5dB
0
1
-7.5dB to -15dB
1
0
-15dB to -22.5dB
1
1
Less than -22.5dB
Setting TEST2.1 = 1 will cause the receive framer to determine if a RCL state exist. Normally (TEST2.1 = 0) the LIU determines the RCL state.
Setting TEST2.0 = 1 will reset the one second timer.
TEST3 (Address AC) can be used to modify the Attenuation Levels of the device.
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