MPC5200B Users Guide, Rev. 1
20-14 Freescale Semiconductor
Memory Map and Registers
20.7.3.6 BDLC Rate Select Register (DLCBRSR) - MBAR + 0x1309
This register determines the divider prescaler value for the mux interface clock (fbdlc). Only integer multiple of the 1 MHz or 1.048576 MHz
fbdlc are supported as input clock.
READ: any time
WRITE: write once in normal and emulation modes.
R7-R0 Rate Select (Bits 7-0)
These bits determine the amount by which the frequency of the system clock signal is divided to generate the MUX Interface clock (fbdlc)
which defines the basic timing resolution of the MUX Interface. The value programmed into these bits is dependent on the chosen system
clock frequency. See Table20-9 and Table 20-10 for example rate selects for different bus frequencies. All divisor values from divide by 1 to
divide by 256 are possible, but are not shown in the tables.
NOTE
Although the maximum divider is 256, a divider which will generate a 1 MHz or 1.048576 MHz fbdlc
must be selected in order for J1850 communications to occur.
01111 15 15
10000 16 16
10001 17 17
10010 18 18
10011 19 19
10100 20 20
10101 21 21
10110 22 22
10111 23 23
11000 24 24
11001 25 25
11010 26 26
11011 27 27
11100 28 28
11101 29 29
11110 30 30
11111 31 31
Note:
1. The transmitter symbol timing adjustment is the same for binary and integer bus frequencies.

Table20-8. BDLC Rate Select Register

msb 01234567 lsb
RR7R6R5R4R3R2R1R0
W
RESET:00000000

Table20-7. BARD Values vs. Transceiver Delay and Transmitter Timing Adjustment (continued)

BARD Offset Bits BO[4:0] Corresponding Expected
Transceiver’s delays (µs)
Transmitter Symbol Timing
Adjustment (tbdlc)1