AN3357| Application Note
Maxim/Dallas > App Notes > TELECOM Keywords: DS2155, DS21458, migration, software migration, SCT, transceiver, quad
Sep 21, 2004
APPLICATION NOTE 3357
DS2155 To DS21458 Migration
The DS21458 is a four-port T1/E1/J1 Single Chip Transceiver (SCT) that shares a common register set with the DS2155, a single port T1/E1/J1 SCT. The DS2155 and the DS21458 share common software architectures, and therefore migrating from the single port DS2155 to the four-port DS21458 is relatively simple. This document details the minor differences between the DS2155 and the DS21458.
Introduction
The DS21458 is a four-port T1/E1/J1 Single Chip Transceiver (SCT) that shares a common register set with the DS2155, a single port T1/E1/J1 SCT. The DS2155 and the DS21458 share common software architectures, and therefore migrating from the single port DS2155 to the four-port DS21458 is relatively simple. This document details the minor differences between the DS2155 and the DS21458.
Register Map
The DS21458 is comprised of four copies of the DS2155 register map, one for each port. The ports are selected via the two most significant address lines, A8 and A9. Though the memory maps are virtually identical, there are several small differences that exist between the DS2155 and the DS21458. These differences are summarized in Table 1 below. Table 1. Register Map Differences Register Name.Bit Address Bit Name DS2155 DS21458 Comments CCR1.3 70h DICAI X -Disable Idle Code Auto Increment - Selects/deselects the auto-increment feature for the transmit and receive idle code array address register, this function is not available in the DS21458 MCLK Select, allows the user to select either TSYSCLK or MCLK as the master clock, this function is not available in the DS21458 Interrupt Disable, allows the user to disable all interrupts regardless of the Interrupt Mask Register settings, this function is not available in the DS21458. Transmit Multi-frame Sync Source, allows the users to select the framer or TSYNC pin
as the source of the multi-frame sync, this feature is not available on the DS21458. LIUC/TPD Pin Function Select, this pin selects the function of the LIUC/TPD pin and should always be set to a 1 in the DS21458. This bit does not exist in the DS2155 memory map. Pulse Shape Adjustment Register 1 - Allows the user to adjust the transmit pulse waveform, this register is not available on the DS2155.
CCR1.7
70h
MCLKS
X
--
CCR3.6
72h
INTDIS
X
--
CCR3.7
72h
TMSS
X
--
LBCR.7
4Ah
LTS
--
X
PSA1
F1h
--
--
X
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