Users can use DS26518 for T1/E1 operations without HDLC controllers.
Procedure to configure DS26518 is described below:
- STEP 1: Reset the device by pulling the RESETB pin low, applying power to the device, or by using the software reset bits outlined in Section 9.3 (in the datasheet). Clear all reset bits. Allow time for the reset recovery.
- STEP 2: Check the Device ID in the IDR register.
- STEP 3: Write the GTCCR1 register to correctly configure the system clocks. If supplying a 1.544MHz MCLK follows this write with at least a 300ns delay in order to allow the clock system to properly adjust.
- STEP 4: Write the entire remainder of the register space for each port with 00h, including reserved register locations.
- STEP 5: Write value 71h to address 1307h. This increases the frequency of the internally generated clock that is supplied to the framers.
- STEP 6: Choose T1/J1 or E1 operation for the framers by configuring the T1/E1 bit in the TMMR and RMMR registers for each framer. Set the FRM_EN bit to 1 in the TMMR and RMMR registers. If using software transmit signaling in E1 mode, program the E1TAF and E1TNAF registers as required.
- STEP 7: Configure the framer Transmit Control Registers (TCR1–TCR4). Configure the framer Receive Control Registers (RCR1–RCR3). Configure other framer features as appropriate.
- STEP 8: Choose T1/J1 or E1 operation for the LIUs by configuring the T1J1E1S bit in the LTRCR register. Configure the line build-out for each LIU. Configure other LIU features as appropriate. Set the TE (transmit enable) bit to turn on the TTIPn and TRINGn outputs.
- STEP 9: Configure the elastic stores, HDLC controller, and BERT as needed.
- STEP 10: Set the INIT_DONE bit in the TMMR and RMMR registers for each framer
The same procedure is applied for DS26514 configuration.