MPC5200B Users Guide, Rev. 1
9-14 Freescale Semiconductor
Programmer’s Model
20:21 AS Address Size field—defines size of peripheral Address bus (in bytes) and must be consistent
with physical connections.
00 = 8 bits
01 = 16 bits
10 = 24 bits
11 = > 25 bits
See documentation for Physical Connection requirements.
The combination of address size, data size, and transaction type (MX) must be consistent
with the peripheral physical connection. In case of a multiplexed transaction, the entire
address is driven regardless of address size field.
cfg operation—If rstcfg[13] on pad_eth_05 is low, then the address size for non-multiplexed
boot device is set to 24 bits (AS=10), else the boot device is treated as a 16 bit address
(AS=01) device. For multiplexed mode boot devices the maximum 25 bits of address is
always driven. This rstcfg bit more particularly affects the DS field below, and can be thought
of as the “small” or “big” data size config bit.
22:23 DS Data Size field—represents the peripheral data bus size (in bytes):
00 =1Byte
01 = 2 Bytes
10 = 3 Bytes (Not Supported)
11 = 4Bytes
cfg operation—If rstcfg[13] on pad_eth_05 is low, then the data size for non-multiplexed
boot device is set to 8 bits (DS=00), else the boot device is treated as a 16 bit (DS=01)
device. For multiplexed mode boot device the selection is 16 bit data or 32 bit data
respectively.
24:25 Bank Bank bits—are reflected on external AD lines (AD[26 :25]) during Address tenure of a
multiplexed transaction. Register bit 24 is the msb and appears on AD[26 ].
26:27 WTyp Wait state Type bits—define the application of wait states contained in WaitP and WaitX
fields, as follows:
00 = WaitX is applied to read and write cycles (WaitP is ignored).
01 = WaitX is applied to Read cycles, WaitP is applied to Write cycles.
10 = WaitX is applied to Reads, WaitP/WaitX (16-bit value) is applied to Writes.
11 = WaitP/Waitx (as a full 16-bit value ) is applied to Reads and Writes.
28 WS Write Swap bit—If high, Endian byte swapping occurs during writes to a peripheral.
For 8-bit peripherals, this bit has no effect.
For 16-bit peripherals, byte swapping can occur.
For 32-bit peripherals (possible in MUXed mode only) byte swap can occur.
1 = swap
0 = NO swap
2-byte swap is AB to BA, 4-byte swap is ABCD to DCBA.
Note: Transactions at less than the defined port size (i.e., data size) apply swap rules as
above, according to the current transaction size.
29 RS Read Swap bit—Same as WS, but swapping is done when reading data from a peripheral.
1 = swap
0 = NO swap
cfg operation—If rstcfg[12] on pad_eth_04 is low, data from the boot device is Endian
swapped when read. This only has effect for boot devices configured as 16- or 32-bit data
size.
Bits Name Description