
System Memory Controller (SMC)
MVME5100 Single Board Computer Programmer’s Reference (6806800H17B
)
216
3.2.6.3
I
2
C Current Address Read
The I
2
C slave device should maintain the last address accessed during the last I
2
C read or write
operation, incremented by one. The first step in the programming sequence should be to test
the i2_cmplt bit for the operation complete status. The next step is to initiate a start sequence
by first setting the i2_start and i2_enbl bits in the I
2
C Control Register and then writing the
device address (bits 7-1) and read bit (bit 0=1) to the I
2
C Transmitter Data Register. The
i2_cmplt bit will be automatically clear with the write cycle to the I
2
C Transmitter Data
Register. The I
2
C Status Register must now be polled to test the i2_cmplt and i2_ackin bits. The
i2_cmplt bit becomes set when the device address and read bit have been transmitted, and the
i2_ackin bit provides status as to whether or not a slave device acknowledged the device
address. With the successful transmission of the device address, the I
2
C master controller
writes a dummy value (data=don’t care) to the I
2
C Transmitter Data Register.This causes the
I
2
C master controller to initiate a read transmission from the slave device. Again, i2_cmplt bit
must be tested for proper response. After the I
2
C master controller has received a byte of data
(indicated by i2_datin=1 in the I
2
C Status Register), the system software may then read the
data by polling the I
2
C Receiver Data Register. The I
2
C master controller does not acknowledge
the read data for a single byte transmission on the I
2
C bus, but must complete the transmission
by sending a stop sequence to the slave device. This can be accomplished by first setting the
i2_stop and i2_enbl bits in the I
2
C Control Register and then writing a dummy data (data=don’t
Содержание MVME5100
Страница 1: ...MVME5100 Single Board Computer Programmer s Reference P N 6806800H17B July 2014...
Страница 8: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B Contents 8 Contents Contents...
Страница 16: ...MVME5100 Single Board Computer Programmer s Reference 6806800H17B 16 List of Figures...
Страница 62: ...Product Data and Memory Maps MVME5100 Single Board Computer Programmer s Reference 6806800H17B 62...
Страница 292: ...Hawk Programming Details MVME5100 Single Board Computer Programmer s Reference 6806800H17B 292...
Страница 308: ...MVME5100 VPD Reference Information MVME5100 Single Board Computer Programmer s Reference 6806800H17B 308...
Страница 312: ...VMEbus Mapping Example MVME5100 Single Board Computer Programmer s Reference 6806800H17B 312...
Страница 316: ...Related Documentation MVME5100 Single Board Computer Programmer s Reference 6806800H17B 316...
Страница 317: ......