ds21ft40 Maxim Integrated Products, Inc., ds21ft40 Datasheet - Page 41

• Manufacturer Part Number: ds21ft40
• Description: Ds21ft40 Four X Three 12 Channel E1 Framer
• Manufacturer: Maxim Integrated Products, Inc.

EBCR1: E–BIT COUNT REGISTER 1 (Address=04 Hex)
EBCR2: E–BIT COUNT REGISTER 2 (Address=05 Hex)
NOTE:
The upper 6 bits of EBCR1 at address 04 are the least significant bits of the 12–bit FAS error counter.
FAS Error Counter
FAS Count Register 1 (FASCR1) is the most significant word and FASCR2 is the least significant word
of a 12–bit counter that records word errors in the Frame Alignment Signal in timeslot 0. This counter is
disabled when RLOS is high. FAS errors will not be counted when the framer is searching for FAS
alignment and/or synchronization at either the CAS or CRC4 multiframe level. Since the maximum FAS
word error count in a one second period is 4000, this counter cannot saturate.
FASCR1: FAS ERROR COUNT REGISTER 1 (Address=02 Hex)
FASCR2: FAS ERROR COUNT REGISTER 2 (Address=04 Hex)
NOTES:
1. The lower 2 bits of FASCR1 at address 02 are the most significant bits of the 10–bit CRC4 error
2. The lower 2 bits of FASCR2 at address 04 are the most significant bits of the 10–bit E–Bit counter.
8. DS0 MONITORING FUNCTION
Each framer in the DS21FT40 has the ability to monitor one DS0 64Kbps channel in the transmit
direction and one DS0 channel in the receive direction at the same time. In the transmit direction the user
will determine which channel is to be monitored by properly setting the TCM0 to TCM4 bits in the CCR4
register. In the receive direction, the RCM0 to RCM4 bits in the CCR5 register need to be properly set.
The DS0 channel pointed to by the TCM0 to TCM4 bits will appear in the Transmit DS0 Monitor
(TDS0M) register and the DS0 channel pointed to by the RCM0 to RCM4 bits will appear in the Receive
DS0 (RDS0M) register. The TCM4 to TCM0 and RCM4 to RCM0 bits should be programmed with the
decimal decode of the appropriate E1 channel. For example, if DS0 channel 6 (timeslot 5) in the transmit
(note 1)
FAS11
(MSB)
(MSB)
FAS5
EB7
SYMBOLS
SYMBOLS
counter.
FAS11
FAS0
EB9
EB0
(note 1)
FAS10
FAS4
EB6
POSITION
POSITION
FASCR1.7
FASCR2.2
(note 1)
EBCR1.1
EBCR2.0
FAS9
FAS3
EB5
(note 1)
FAS8
FAS2
EB4
NAME AND DESCRIPTION
MSB of the 10–Bit E–Bit Error Count
LSB of the 10–Bit E–Bit Error Count
NAME AND DESCRIPTION
MSB of the 12–Bit FAS Error Count
LSB of the 12–Bit FAS Error Count
(note 1)
FAS7
FAS1
EB3
41 of 87
(note 1)
FAS6
FAS0
EB2
(note 2)
(note 1)
EB9
EB1
(note 2)
(note 1)
(LSB)
(LSB)
EB8
EB0
FASCR1
FASCR2
EBCR1
EBCR2
DS21FT40