HDLC Configuration of Framers

Abstract: ApplicaTIon Note 394 contains guidelines showing how to use the necessary operaTIon modes inside our framers, transceivers or single-chip transceivers (SCTs) to route HDLC data. This applicaTIon note lists the register descripTIons of different operation modes of our different framers and transceivers, enabling the user to select the proper configuration.

This application note applies to the following products:

FRAMERS SCTs T1 E1 T1 E1 T1/E1/J1 DS21Q42 DS21Q44 DS21352 DS21354 DS2155 DS21FT42 DS21FT44 DS21552 DS21554 DS2156 DS21FF42 DS21FF44 DS21Q352 DS21Q354 DS21Q55 DS21Q552 DS21Q554 DS21E55
1. DS21352, DS21552, and DS21Q42The DS21352, DS21552, and DS21Q42 have the ability to route the HDLC data through the facilities data link (FDL) via a single DS0 or multiple DS0s. Table 1-1 shows the registers used for selecting HDLC operational mode. While the HDLC transmitter can be disabled, the HDLC receiver cannot. If operation of the HDLC receiver is not desired, it can be ignored without affecting the system.

Table 1-1. HDLC Control Registers REGISTER HDLC ADDRESS FUNCTION TDC1 0x92 Transmit HDLC control register #1 RDC1 0x90 Receive HDLC control register #1 TBOC 0x07 Transmit BOC control register TCR1 0x35 Transmit control register #1 TCBR1
...
TCBR3 0x32
...
0x34 Transmit channel blocking registers/Transmit HDLC channel selection registers RCBR1
...
RCBR3 0x6C
...
0x6E Receive channel blocking registers/Receive HDLC channel selection registers

The following tables list the different configurations that exist for the HDLC inside the DS21352, DS21552, and DS21Q42 devices. Throughout this section, the terms DS0, time slot, and channel refer to a single 64kbps data stream and can be used interchangeably.

HDLC Transmit ConfigurationTable 1-2. Transmit control register mode selection Mode TDC1.7 TDC1.5 TBOC.6 TCR1.2 FUNCTION TDS0E TDS0M HBEN TFDLS 0 0 X 0 X Disable transmit HDLC 1 0 X 1 1 HDLC routed through the FDL 2 1 0 0 X HDLC routed through a single DS0 3 1 1 0 X HDLC routed through multiple DS0sX = don't care

Table 1-3. Transmit control register bit and channel selection Mode TDC1.4 TDC1.3 TDC1.2 TDC1.1 TDC1.0 FUNCTION TD4 TD3 TD2 TD1 TD0 1 Sa4 Sa5 Sa6 Sa7 Sa8 Sa bit routing defined by TD4-TD0 2 Bit4 Bit3 Bit2 Bit1 Bit0 DS0 routing defined by TD4-TD0 3 X X X X X DS0s routing defined by TCBR1-TCBR4X = don't care

HDLC Receive ConfigurationTable 1-4. Receive control register mode selection Mode RDC1.7 RDC1.5 FUNCTION RDS0E RDS0M 0 0 X HDLC routed through the FDL 1 1 0 HDLC routed through a single DS0 2 1 1 HDLC routed through multiple DS0sX = don't care

Table 1-5. Receive control register bit and channel selection Mode TDC1.4 TDC1.3 TDC1.2 TDC1.1 TDC1.0 FUNCTION RD4 RD3 RD2 RD1 RD0 0 X X X X X HDLC routed through the FDL 2 Bit4 Bit3 Bit2 Bit1 Bit0 DS0 routing defined by RD4-RD0 3 X X X X X DS0s routing defined by RCBR1-RCBR4X = don't care

Legacy FDL ConfigurationWhen using the internal HDLC and BOC controller to route data through the FDL, the legacy FDL circuitry should be disabled. Table 1-6 shows a listing of the legacy FDL registers and how to program them to disable legacy FDL operation.

Table 1-6. Legacy FDL Control Registers REGISTER NAME VALUE FUNCTION TCR1.2 TFDLS 1 Source FDL data from the HDLC and BOC controller TBOC.6 HBEN 1 Enable HDLC and BOC controller CCR2.5 TSLC96 0 Disable SLC-96 and D4 Fs-bit insertion CCR2.4 TFDL 0 Disable legacy transmit FDL zero destuffer CCR2.1 RSLC95 0 Disable SLC-96 reception CCR2.0 RZSE 0 Disable legacy receive FDL zero destuffer IMR2.4 RFDL 0 Disable legacy receive FDL buffer full interrupt IMR2.3 TFDL 0 Disable legacy transmit FDL zero stuffer IMR2.2 RMTCH 0 Disable legacy FDL match interrupt IMR2.1 RAF 0 Disable legacy FDL abort interrupt
2. DS21354, DS21554, DS21Q44The DS21354, DS21554, and DS21Q44 can route the HDLC data through the Sa bit positions (Sa4 to Sa8) via a single DS0 or multiple DS0s. Operational mode selection of the HDLC is accomplished using the registers described in Table 2-1. While the HDLC transmitter can be disabled, the HDLC receiver cannot. If operation of the HDLC receiver is not desired, it can be ignored without affecting the system.

Table 2-1. HDLC Control Registers REGISTER HDLC ADDRESS FUNCTION TDC1 0xBA Transmit HDLC control register #1 RDC1 0xB8 Receive HDLC control register #1 RCR2 0x11 Receive control register #2 TCBR1
...
TCBR4 0x22
...
0x25 Transmit channel blocking registers/Transmit HDLC channel selection registers RCBR1
...
RCBR4 0x2B
...
0x2E Receive channel blocking registers/Receive HDLC channel selection registers

The tables below list the different configurations that exist for the HDLC inside the DS21354, DS21554, and DS21Q44 devices. Throughout this section, the terms DS0, time slot, and channel refer to a single 64kbps data stream and can be used interchangeably.

HDLC Transmit ConfigurationTable 2-2. Transmit control register mode selection Mode TDC1.7 TDC1.6 TDC1.5 FUNCTION THE TSaDS TDS0M 0 0 X X Disable transmit HDLC 1 1 0 X HDLC routed through the Sa bits 2 1 1 0 HDLC routed through a single DS0 3 1 1 1 HDLC routed through multiple DS0sX = don't care

Table 2-3. Transmit control register bit and channel selection Mode TDC1.4 TDC1.3 TDC1.2 TDC1.1 TDC1.0 FUNCTION TD4 TD3 TD2 TD1 TD0 1 Sa4 Sa5 Sa6 Sa7 Sa8 Sa bit routing defined by TD4-TD0 2 Bit4 Bit3 Bit2 Bit1 Bit0 DS0 routing defined by TD4-TD0 3 X X X X X DS0s routing defined bt TCBR1-TCBR4X = don't care

HDLC Receive ConfigurationTable 2-4. Receive control register mode selection Mode RDC1.7 RDC1.6 RDC1.5 FUNCTION RHS RSaDS RDS0M 0 0 X X HDLC routed through the Sa bits with RLCLK active 1 1 0 X HDLC routed through the Sa bits 2 1 1 0 HDLC routed through a single DS0 3 1 1 1 HDLC routed through multiple DS0sX = don't care

Table 2-5. Receive control register bit and channel selection Mode TDC1.4 TDC1.3 TDC1.2 TDC1.1 TDC1.0 FUNCTION RD4 RD3 RD2 RD1 RD0 0 X X X X X Sa bit routing defined by RCR2.3-RCR2.7 1 Sa4 Sa5 Sa6 Sa7 Sa8 Sa bit routing defined by RD4-RD0 2 Bit4 Bit3 Bit2 Bit1 Bit0 DS0 routing defined by RD4-RD0 3 X X X X X DS0s routing defined by RCBR1-RCBR4X = don't care

3. DS21354, DS21554, and DS21Q44; DS21352, DS21552, and DS21Q42 HDLC General Time Slot ConfigurationWhen using the HDLC to route data through a single time slot or multiple time slots, there are two ways to assign which of the 32 time slots carry data. When only using a single time slot to route data, it can be defined by the TD4-TD0 and RD4-RD0 bits in the TDC1 and RDC1 registers, respectively. When using multiple time slots to route data, the channel blocking registers TCHBLK and RCHBLK are used for assigning which time slots are used for routing data.

In addition to controlling which time slots data is routed through, any combination of bits within the time slots can be blocked to limit data flow in the time slots. This is accomplished by configuring the transmit and receive HDLC control registers #2 (TDC2 at address 0x93 and RDC2 at address 0x91) to block the unused bits. See Tables 3-1 and 3-2 for details about blocking unused bits in each time slot.

Table 3-1. Transmit HDLC DS0 bit suppression TDC2.7 TDC2.6 TDC2.5 TDC2.4 TDC2.3 TDC2.2 TDC2.1 TDC2.0 FUNCTION TDB8 TDB7 TDB6 TDB4 TDB3 TDB2 TDB1 TDB0 A A A A A A A A DS0 Block BitsA = 0 (active), 1 (inactive)

Table 3-2. Receive HDLC DS0 bit suppression RDC2.7 RDC2.6 RDC2.5 RDC2.4 RDC2.3 RDC2.2 RDC2.1 RDC2.0 FUNCTION RDB8 RDB7 RDB6 RDB4 RDB3 RDB2 RDB1 RDB0 A A A A A A A A DS0 Block BitsA = 0 (active), 1 (inactive)

4. DS2155 and DS2156The DS2155 and DS2156 have two HDLC controllers that have the ability to route the HDLC data through data via the FDL in T1 mode, the Sa bit positions (Sa4 to Sa8) in E1 mode, via a single DS0, or multiple DS0s. The two HDLC controllers, HDLC #1 and HDLC #2, are independently controlled by two sets of identical registers. Selection for the HDLC operation mode is accomp lished using the registers described in Table 4-1.

Table 4-1. HDLC control registers REGISTER HDLC #1 ADDRESS HDLC #2 ADDRESS FUNCTION HxTC 0x90 0xA0 Transmit HDLC control register HxRC 0x31 0x32 Receive HDLC control register HxTTSBS 0x9B 0xAB Transmit HDLC Sa/DS0 bit selection register HxRTSBS 0x96 0xA6 Receive HDLC Sa/DS0 bit selection register HxTCS1
...
HxTCS4 0x97
...
0x9A 0xA7
...
0xAA Transmit HDLC channel selection registers HxRCS1
...
HxRCS4 0x92
...
0x95 0xA2
...
0xA5 Receive HDLC channel selection registers

The tables below list the different configurations for the HDLC controllers inside the DS2155 and DS2156 devices. Throughout this section, the terms DS0, time slot, and channel refer to a single 64kbps data or voice stream and can be used interchangeably. It should also be noted that the two HDLC controllers should not be mapped simultaneously to the FDL in T1 mode, the same Sa bits in E1 mode, or the same time slots.

HDLC Transmit ConfigurationTable 4-2. Transmit control register mode selection MSTRREG.1 HxTC.4 HxTCS1/2/3/4 FUNCTION T1/E1 THMS X 0 0x00 Disable transmit HDLC 0 1 NA HDLC routed through the FDL 1 1 NA HDLC routed through the Sa bits X 0 CE HDLC routed through single/multiple DS0X = don't care, NA = not applicable, CE = channel enables

Table 4-3. Transmit HDLC Sa bit selection in E1 mode HxTTSBS.7 HxTTSBS.6 HxTTSBS.5 HxTTSBS.4 HxTTSBS.3 HxTTSBS.2 HxTTSBS.1 HxTTSBS.0 TCB8SE TCB7SE TCB6SE TCB5SE TCB4SE TCB3SE TCB2SE TCB1SE X X X Sa4 Sa5 Sa6 Sa7 Sa8X = don't care; SaX = 0 (disable), 1 (enable)

Table 4-4. Transmit HDLC DS0 channel selection MODE HxTCS1 HxTCS2 HxTCS3 HxTCS4 Channels 8-1 Channels 16-9 Channels 24-17 Channels 32-25 T1 CCCCCCCC CCCCCCCC CCCCCCCC XXXXXXXX E1 CCCCCCCC CCCCCCCC CCCCCCCC CCCCCCCCX = don't care; C = 0(deselect channel), 1 (select channel)

Table 4-5. Transmit HDLC DS0 bit suppression HxTTSBS.7 HxTTSBS.6 HxTTSBS.5 HxTTSBS.4 HxTTSBS.3 HxTTSBS.2 HxTTSBS.1 HxTTSBS.0 TCB8SE TCB7SE TCB6SE TCB5SE TCB4SE TCB3SE TCB2SE TCB1SE A A A A A A A AA = 0 (active), 1 (inactive)

HDLC Receive ConfigurationTable 4-6. Receive control register mode selection MSTRREG.1 HxTC.4 HxTCS1/2/3/4 FUNCTION T1/E1 THMS X 0 0x00 Disable transmit HDLC 0 1 NA HDLC routed through the FDL 1 1 NA HDLC routed through the Sa bits X 0 CE HDLC routed through single/multiple DS0X = don't care, NA = not applicable, CE = channel enables

Table 4-7. Receive HDLC Sa bit selection in E1 mode HxRTSBS.7 HxRTSBS.6 HxRTSBS.5 HxRTSBS.4 HxRTSBS.3 HxRTSBS.2 HxRTSBS.1 HxRTSBS.0 RCB8SE RCB7SE RCB6SE RCB5SE RCB4SE RCB3SE RCB2SE RCB1SE X X X Sa4 Sa5 Sa6 Sa7 Sa8X = don't care; SaX = 0 (disable), 1 (enable)

Table 4-8. Receive HDLC DS0 channel selection MODE HxRCS1 HxRCS2 HxRCS3 HxRCS4 Channels 8-1 Channels 16-9 Channels 24-17 Channels 32-25 T1 CCCCCCCC CCCCCCCC CCCCCCCC XXXXXXXX E1 CCCCCCCC CCCCCCCC CCCCCCCC CCCCCCCCX = don't care; C = 0(deselect channel), 1 (select channel)

Table 4-9. Receive HDLC DS0 bit suppression HxRTSBS.7 HxRTSBS.6 HxRTSBS.5 HxRTSBS.4 HxRTSBS.3 HxRTSBS.2 HxRTSBS.1 HxRTSBS.0 RCB8SE RCB7SE RCB6SE RCB5SE RCB4SE RCB3SE RCB2SE RCB1SE A A A A A A A AA = 0 (active), 1 (inactive)

Legacy FDL ConfigurationWhen using the internal HDLC and BOC controller to route data through the FDL in T1 mode, the legacy FDL circuitry should be disabled. Table 22 shows a listing of the legacy FDL registers and how to program them to disable legacy FDL operation.

Table 4-10. Legacy FDL Control Registers BITMAP NAME VALUE FUNCTION T1TCR1.2 TFDLS 1 Source FDL data from the HDLC controller T1TCR2.6 TSCL96 0 Disable SLC-96 and D4 Fs-bit insertion T1TCR2.5 TZSE 0 Disable legacy transmit FDL zero destuffer T1RCR2.4 RSLC96 0 Disable SLC-96 reception T1RCR2.3 RZSE 0 Disable legacy receive FDL zero destuffer IMR8.3 RFDLF 0 Disable legacy receive FDL buffer full interrupt IMR8.2 TFDLE 0 Disable legacy transmit FDL zero stuffer IMR8.1 RMTCH 0 Disable legacy FDL match interrupt IMR8.4 RFDLAD 0 Disable legacy FDL abort interrupt