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SZEN — Enable SIZ signal to UART CH1 pins
This bit is used to select the function provided by the UART channel 1 pins. On reset,
this bit is cleared.
0 = UART channel 0 operation. Pins function as TxD1, RxD1.
1 = SIZ function operation. Pins function as TSIZ0 and TSIZ1 outputs indepen-
dent of function or direction programmed in UART channel 1 control regis-
ters.
PSTEN — Enable PSTAT signals to UART CH0 pins
This bit is used to select the function provided by the UART channel 0 pins. On reset,
this bit is cleared.
0 = UART channel 0 operation. Pins function as TxD0, RxD0, CTS0, and RTS0.
1 = PSTAT function operation. Pins function as PSTAT outputs independent of
function or direction programmed in UART channel 0 control registers.
SPRAM — Internal RAM Supervisor Protect
This bit is used to restrict accesses to the internal RAM space if the access is
attempted in the user mode of CPU operation. On reset, this bit is set.
0 = User mode accesses are allowed to the internal RAM.
1 = User mode accesses are prohibited. An attempted access to the internal
RAM in user mode will result in TEA assertion to the CPU.
SPROM — Internal ROM Supervisor Protect
This bit is used to restrict accesses to the internal ROM space if the access is
attempted in the user mode of CPU operation. On reset, this bit is set.
0 = User mode accesses are allowed to the internal ROM.
1 = User mode accesses are prohibited. An attempted access to the internal
ROM in user mode will result in a TEA to the CPU.
HDB — High Data Bus
This bit is used to determine which byte lanes of the internal data bus are driven onto
the external data bus when show cycles are enabled. This bit is ignored if SHEN is
cleared.
0 = Lower internal data bus bits DATA[15:0] are driven externally.
1 = Upper internal data bus bits DATA[31:16] are driven externally.
SHEN — Show Cycle Enable
These two bits are used to determine what the EIM does with the external bus during
internal transfers (i.e., an access to the internal ROM, RAM or peripherals). When
show cycles are enabled, the internal address and data bus are driven externally. On
reset, show cycles are disabled.
MOTOROLA
7-12
Freescale Semiconductor, Inc.
EXTERNAL INTERFACE MODULE
For More Information On This Product,
Go to: www.freescale.com
MMC2001
REFERENCE MANUAL
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