Chapter 3: Programming the Peripherals

NOTE

For T1/J1 applications, the mapping of the receive 24 line time slots over the 32 available on the system interface is configurable with FMR1.CTM bit. In 4538 Boot firmware, the choice is to select ‘Channel translation mode 1’, by setting FRM1.CTM bit to 1: on reception, the 24 line time slots are contiguously mapped before they are interleaved on the system bus. The same mapping occurs on transmission.

Table 3-2. Channel Phase Programming in Multiplexed System Data Streams

Channel SIC2.SICS2...0

￿￿￿￿

￿￿￿￿

￿￿￿￿

￿￿￿￿

RCLK1 Configuration as TDM Bus Clock

See Boot Firmware sources: tst\c\qfalc.c - Function gvQFalcSetPortSyncSrc.

RCLK1 signal of QuadFALC is recovered from the line and dejittered by DCO-R. It must be configured as an active output (PC5.CRP = 1). RCLK2, RCLK3, and RCLK4 shall be configured as inputs (PC5.CRP = 0).

RCLK1 is one of the four channels’ internally generated receive route clocks (RCLK) (a channel is a FALC within a QuadFALC) of a QuadFALC: the channel selection is set with GPC1.R1S1 and GPC1.R1S0 bits – when using RCLK1 for synchronizing the TDM SIxRAM, an active channel should be selected. On each channel, program CMR1.RS1=1 and CMR1.RS0=1: the advantage would be to have RCLK1 at 8.192 MHz whatever the source’s channel mode is (T1/J1 or E1), the disadvantage is that in case of an LOS (Loss Of Signal) on the source channel, RCLK1 does not go to a continuous level, but is the free running frequency of DCO-R. Since DCO-R is used, program CMR1.DRSS1 and CMR.DRSS0 bits as shown in Table 3-3to select the reference source for the DCO-R circuit.

Table 3-3. QuadFALC RCLK Reference Source for DCO-R

Channel

CMR1.DRSS1

CMR1.DRSS0

 

 

 

￿

￿

￿

 

 

 

￿

￿

￿

 

 

 

￿

￿

￿

 

 

 

￿

￿

￿

 

 

 

4538 Hardware Reference Manual

77