11-22
MCF5272 User’s Manual
Programming Model
Table 11-18. describes the X_WMRK fields.
11.5.12 FIFO Transmit Start Register (X_FSTART)
The X_FSTART register, Figure 11-15, can be programmed by the user to indicate the
starting address of the transmit FIFO. Usually there is no need to program X_FSTART. For
optimal RAM allocation, do not program X_FSTART to a value less than its reset value.
The value in this register must be added to MBAR + 0x800 to determine the absolute
address.
The X_FSTART register is reset to the first available RAM address.
31
16
Field
—
Reset
0000_0000_0000_0000
R/W
Read/Write
15
2
1
0
Field
—
X_WMRK
Reset
0000_0000_0000_00
00
R/W
Read/Write
Addr
MBAR + 0x8E4
Figure 11-14. Transmit FIFO Watermark (X_WMRK)
Table 11-18. X_WMRK Field Descriptions
Bits
Name
Description
31–2
—
Reserved, should be cleared.
1–0
X_WMRK
Transmit FIFO watermark. Frame transmission begins when the number of bytes
selected by this field are written into the transmit FIFO, if an end of frame has been
written to the FIFO, or if the FIFO is full before the selected number of bytes are
written. The options are:
0X 64 bytes written to transmit FIFO
10 128 bytes written to transmit FIFO
11 192 bytes written to transmit FIFO
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
Страница 38: ...xxxviii MCF5272 User s Manual TABLES Table Number Title Page Number ...
Страница 58: ...1 10 MCF5272 User s Manual MCF5272 Specific Features ...
Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
Страница 338: ...13 44 MCF5272 User s Manual Application Examples ...
Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
Страница 482: ...20 30 MCF5272 User s Manual Reset Operation ...
Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...