Read Operation by the Master
2-5
MSP53C691 Hardware Description
2.3
Read Operation by the Master
The process for the read operation by the master is the same in 4-bit and 8-bit
modes. The read operation by the master happens when the slave wants to
send something to the master. The slave initiates the read process by pulling
OUTRDY low when the slave is ready.
The following events take place during the read operation:
1) The MSP53C691 puts the data to be sent to the master on the internal bus.
2) The MSP53C691 sets OUTRDY low to indicate that it is ready to send data
to the microcontroller.
3) The microcontroller sets R/W high to indicate a read operation.
4) The microcontroller sets STROBE low. The data is available on the exter-
nal data-bus at this point.
5) The microcontroller reads the data from the bus.
6) The microcontroller sets STROBE high. The MSP53C691 also pulls
OUTRDY high at the rising edge of STROBE.
7) The data is taken off from the external data-bus after STROBE goes high.
The microcontroller must latch or read in the data while STROBE is low. When
the microcontroller sets STROBE high, the MSP53C691 sets OUTRDY high
to indicate that the data has been successfully transferred.
Figure 2–3 shows the sequence of events of the read operation.
Figure 2–3. Data Transfer—Read
b) Read—Two speech data transfer sequences:
a) Sequence of events for a single read operation:
DATA
COMMAND/DATA
DATA
COMMAND/DATA
R/W
R/W
OUTRDY
STROBE
OUTRDY
STROBE
Содержание MSP53C691
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