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CHAPTER 3 SYSTEM CONTROLLER
Preliminary User’s Manual S14767EJ1V0UM00
227
3.2.2 General registers
3.2.2.1 General Mode Register (S_GMR)
The General Mode Register “S_GMR” is read-write and word aligned 32bit register. After initializing, V
R
4120A set
the IAEN bit to enable the IBUS arbiter. S_GMR is initialized to 0 at reset and contains the following fields:
Bits
Field
Description
0
CRST
Cold Reset:
0 = do nothing
1 = perform cold reset (same as hardware system reset)
1
IAEN
IBUS Arbiter Enable:
0 = disable (IBUS Arbiter does not allow the grant except System Controller)
1 = enable.
2
MPFD
Memory-to-CPU Prefetch FIFO disable:
0 = enable
1 = disable
3
UCSEL
UART Source Clock Selection:
0 = use 1/2 of CPU clock
1 = use external clock (18.432MHz)
7:4
Reserved
Hardwired to 0.
8
HSWP
HIF Block Data swap function enable:
0 = enable
1 = disable
9
MSWP
MIF Block Data swap function enable:
0 = enable
1 = disable
31:10
Reserved
Hardwired to 0.
3.2.2.2 General Status Register (S_GSR)
The General Status Register “S_GSR” is read-only and word aligned 32bit register. S_GSR shows the status of
external pin of the
μ
PD98501. S_GSR contains the following fields:
Bits
Field
Description
0
ENDCEN
This field reflects the status of external pin “ENDCEN” after reset.
0 = connected to GND, It means that Endian Converter is disabled.
1 = connected to VCC, It means that Endian Converter is enabled.
1
CCLKSEL
This field reflects the status of external pin “CCLKSEL” after reset.
0 = connected to GND, It means that CPU is operated at 100MHz.
1 = connected to VCC, It means that CPU is operated at 66MHz.
31:2
Reserved
Hardwired to 0.