MPC563XM Reference Manual, Rev. 1
322
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
The AD_MUX bit controls whether accesses for this chip select have the address driven on the data
bus in the address phase of a cycle
1 = Address on Data Multiplexing Mode is enabled for this chip select.
0 = Address on Data Multiplexing Mode is disabled for this chip select.
BL — Burst Length
The BL bit determines the amount of data transferred in a burst for this chip select, measured in 32-bit
words. The number of beats in a burst is automatically determined by the EBI to be 4, 8, or 16
according to the Port Size (PS bit) so that the burst fetches the number of words chosen by BL (see
). For internal AMBA data bus width of 32-bits, the BL bit is ignored (treated as 1).
NOTE
The EBI does NOT support a 2-word external burst length. This means that
neither a 4-beat burst to a 16-bit external memory (nor a 2-beat burst to
32-bit external memory) are supported.
WEBS — Write Enable / Byte Select
This bit controls the functionality of the WE[0:3]/BE[0:3] signals.
1 = The WE[0:3]/BE[0:3] signals function as BE[0:3]
0 = The WE[0:3]/BE[0:3] signals function as WE[0:3]
TBDIP — Toggle Burst Data in Progress
This bit determines how long the BDIP signal is asserted for each data beat in a burst cycle. See
Section 13.5.2.5.1, “TBDIP Effect on Burst Transfer
for details.
1 = Only assert BDIP (BSCY+1) external cycles before expecting subsequent burst data beats
0 = Assert BDIP throughout the burst cycle, regardless of wait state configuration
SETA — Select Transfer Acknowledge
SETA — Select External Transfer Acknowledge
Table 13-10. BL Values
Value
Burst
Length
1
1
Total amount of data fetched in a burst transfer.
PS
# Beats in Burst
2
2
Number of external data beats used in external burst transfer. The
size of each beat is determined by PS value.
0
3
3
An 8-word burst length is only supported for SoC’s using 64-bit
AMBA data bus width to EBI.
8-word
4
4
A word always refers to 32-bits of data, regardless of PS.
0 (32-bit)
8
1 (16-bit)
16
1
4-word
0 (32-bit)
4
1 (16-bit)
8