34-8
MPC8260 PowerQUICC II UserÕs Manual
MOTOROLA
Part IV. Communications Processor Module
Table 34-3 describes I2BRG Þelds.
34.4.4 I
2
C Event/Mask Registers (I2CER/I2CMR)
The I
2
C event register (I2CER) is used to generate interrupts and report events. When an
event is recognized, the I
2
C controller sets the corresponding I2CER bit. I2CER bits are
cleared by writing ones; writing zeros has no effect. Setting a bit in the I
2
C mask register
(I2CMR) enables and clearing a bit masks the corresponding interrupt. Unmasked I2CER
bits must be cleared before the CP clears internal interrupt requests. Figure 34-9 shows both
registers.
Table 34-4 describes the I2CER/I2CMR Þelds.
34.4.5 I
2
C Command Register (I2COM)
The I
2
C command register, shown in Figure 34-10, is used to start I
2
C transfers and to select
master or slave mode.
Table 34-3. I2BRG Field Descriptions
Bits
Name
Description
0Ð7
DIV
Division ratio 0Ð7. SpeciÞes the divide ratio of the BRG divider in the I
2
C clock generator. The output of
the prescaler is divided by 2 * ([DIV0ÐDIV7] + 3) and the clock has a 50% duty cycle. DIV must be
programmed to a minimum value of 3 if the digital Þlter is disabled and 6 if it is enabled.
Bit
0
1
2
3
4
5
6
7
Field
Ñ
TXE
Ñ
BSY
TXB
RXB
Reset
0000_0000
R/W
R/W
Addr
0x11870(I2CER)/0x11874 I2CMR)
Figure 34-9. I
2
C Event/Mask Registers (I2CER/I2CMR)
Table 34-4. I2CER/I2CMR Field Descriptions
Bits Name
Description
0Ð2
Ñ
Reserved and should be cleared.
3
TXE
Tx error. Set when an error occurs during transmission.
4
Ñ
Reserved and should be cleared.
5
BSY
Busy. Set after the Þrst character is received but discarded because no Rx buffer is available.
6
TXB
Tx buffer. Set when the Tx data of the last character in the buffer is written to the Tx FIFO. Two character
times must elapse to guarantee that all data has been sent.
7
RXB
Rx buffer. Set after the last character is written to the Rx buffer and the RxBD is closed.
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
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Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
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